[Federal Register Volume 59, Number 49 (Monday, March 14, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-5854]
[[Page Unknown]]
[Federal Register: March 14, 1994]
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
Endangered and Threatened Wildlife and Plants; 90-day Finding on
a Petition To Delist Seven Texas Karst Invertebrates
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Notice of petition finding.
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SUMMARY: The U.S. Fish and Wildlife Service (Service) announces a 90-
day finding on a petition to remove seven species of invertebrates that
occur in karst topography in Travis and Williamson counties, Texas,
from the List of Endangered and Threatened Wildlife and Plants. The
Service determines that the petition does not present substantial
scientific or commercial information indicating that delisting the
Coffin Cave mold beetle (Batrisodes texanus), the Tooth Cave spider
(Neoleptoneta myopica), the Tooth Cave ground beetle (Rhadine
persephone), the Tooth Cave pseudoscorpion (Tartarocreagris texana),
the Kretschmarr Cave mold beetle (Texamaurops reddelli), the Bee Creek
Cave harvestman (Texella reddelli), and the Bone Cave harvestman
(Texella reyesi) may be warranted.
DATES: The finding announced in this notice was made on March 7, 1994.
Comments and information related to this petition finding may be
submitted until further notice.
ADDRESSES: Information, comments, or questions may be submitted to the
State Administrator, U.S. Fish and Wildlife Service, Ecological
Services Field Office, 611 East 6th Street, room 407, Austin, Texas
78701. The petition, finding, supporting data, and comments will be
available for public inspection, by appointment, during normal business
hours at the above address.
FOR FURTHER INFORMATION CONTACT: Ruth Stanford, Ecologist, at the above
address (512/482-5436).
SUPPLEMENTARY INFORMATION:
Background
Section 4(b)(3)(A) of the Endangered Species Act of 1973, as
amended (16 U.S.C. 1531 et seq.) (Act), requires that the Service make
a finding on whether a petition to list, delist, or reclassify a
species presents substantial scientific or commercial information
indicating that the petitioned action may be warranted. To the maximum
extent practicable, this finding is to be made within 90 days of
receipt of the petition, and the finding is to be published promptly in
the Federal Register. If the finding is positive, the Service is also
required to promptly commence a status review of the species.
Judge John C. Doerfler, representing the Williamson County
Commissioners Court, submitted a petition to the Service to delist six
species of endangered karst invertebrates in Travis and Williamson
counties, Texas. The petition was dated June 7, 1993, and received by
the Service on that date. On June 16, 1993, the Service received a
letter from attorney J.B. Ruhl on behalf of the petitioners, clarifying
the intent of the petition to incorporate recent taxonomic revisions
and the taxonomic reevaluation of five listed karst invertebrate
species as seven species.
The final rule listing the Tooth Cave pseudoscorpion (Microgreagris
texana), the Tooth Cave spider (Leptoneta myopica), the Bee Creek Cave
harvestman (Texella reddelli), the Tooth Cave ground beetle (Rhadine
persephone), and the Kretschmarr Cave mold beetle (Texamaurops
reddelli) as endangered species was published in the Federal Register
on September 16, 1988 (53 FR 36029) (final rule). Subsequent taxonomic
revisions have formalized genus reassignments for M. texana and L.
myopica and established that Texella reddelli and Texamaurops reddelli
each actually comprise two species. Microcreagris texana has been
reassigned to Tartarocreagris texana (Muchmore 1992). Leptoneta myopica
has been formally reassigned to Neoleptoneta myopica following Brignoli
(1977) and Platnick (1986). Texella reddelli has been found to comprise
two species, Texella reddelli (Bee Creek Cave harvestman) and Texella
reyesi (Bone Cave harvestman) (Ubick and Briggs 1992). Texamaurops
reddelli has been found to comprise two species, Texamaurops reddelli
(Kretschmarr Cave mold beetle) and Batrisodes texanus (Coffin Cave mold
beetle) (Chandler 1992). A Federal Register notice announcing the
latter two revisions was published on August 18, 1993 (58 FR 43818).
Several caves in Travis County contain more than one of the
endangered karst invertebrates. These include Tooth Cave, Amber Cave,
Gallifer Cave, Kretschmarr Cave, and Kretschmarr Double Pit. These
caves and others are protected under the stewardship of the Texas
System of Natural Laboratories (TSNL). In addition, some other caves
are in preserves regulated by the Cities of Austin and Georgetown. (For
further discussion, see Factor D, ``The inadequacy of existing
regulatory mechanisms,'' below.) However, many of the caves containing
endangered karst invertebrates currently have no protection other than
that provided by the Act.
The petitioners point out that, since publication of the final
rule, new locations have been discovered for several of the species,
most notably the Tooth Cave ground beetle and the Bone Cave harvestman.
The Tooth Cave ground beetle was known from two caves about 2.5
kilometers (km) (1.5 miles (mi)) apart in Travis County, Texas, at the
time of listing. It is currently known from about 27 locations (24
confirmed, 3 tentative) along a 14-km (9-mi) distance in Travis and
Williamson counties, Texas. Only 10 of these caves are provided any
degree of local protection (James Reddell, Texas Memorial Museum, in
litt., 1993). Seven of these caves are located in the small TSNL
preserves discussed above, one is in a small preserve owned by the City
of Austin, and two are in small preserves acquired as mitigation for a
development project.
The Bone Cave harvestman was not described at the time of the
original listing, but was thought to be the same species as the Bee
Creek Cave harvestman. The Bone Cave harvestman is currently known from
about 69 locations (60 confirmed, 9 tentative) along a 40-km (25-mi)
distance in Travis and Williamson counties, Texas. Of the 69 caves
recorded as locations of the Bone Cave harvestman, only 9 are provided
any local protection. Three are TSNL caves, two are in City of Austin
preserves, two are in City of Georgetown preserves, and two were
acquired as mitigation for a development project. In addition, this
species exhibits considerable geographical variation and loss of a
significant number of locations within a part of its range would result
in a loss of genetic diversity within the species (Reddell, in litt.,
1993). Few caves are provided any protection other than that now
provided by the Act and their distribution is disjunct and at the
extremes of the species' range.
The number of caves in which the other five endangered karst
invertebrates have been found or tentatively identified has increased
slightly for three of the species, remained the same for another
species (although its range has decreased), and decreased for the fifth
species.
The Tooth Cave pseudoscorpion, known at the time of listing from
Tooth and Amber caves, within a 1.3-km (0.8-mi) radius in Travis
County, remains confirmed only from the two original caves. The species
has been tentatively identified from Stovepipe Cave and Kretschmarr
Double Pit, lying within the original range. Stovepipe Cave is located
on private property that the City of Austin has approved for
development. The three remaining caves are located in the small TSNL
preserves discussed above.
The Tooth Cave spider, known at the time of listing only from Tooth
Cave, is now also confirmed at New Comanche Trail Cave and tentatively
identified from Gallifer and Stovepipe caves, all lying along a 4.5-km
(3-mi) distance in northwest Travis County, Texas. Tooth and Gallifer
caves lie within small TSNL preserves, Stovepipe Cave is on private
property approved for development, and New Comanche Trail Cave is not
protected and may be adversely impacted by a planned realignment of New
Comanche Trail Road.
The Coffin Cave mold beetle was not described at the time of
listing, but was thought to belong to the same species as the
Kretschmarr Cave mold beetle. The Coffin Cave mold beetle is currently
confirmed from four caves and tentatively identified from one cave, all
occurring along a 17-km (10-mi) distance in Williamson County, Texas.
Off Campus and Sierra Vista caves are located in a small preserve
surrounded by a subdivision; the adequacy of the preserve for long-term
protection of the species at those sites is uncertain. On Campus Cave
lies on a high school campus. The status of the type locality (Coffin
Cave) is unknown; recent attempts to locate the species in Inner Space
Cavern were unsuccessful (Reddell, in litt., 1993).
The Kretschmarr Cave mold beetle was believed to occur in four
caves in Travis and Williamson counties at the time of listing and is
currently known from four caves in Travis County. A specimen from
Coffin Cave was redescribed as the Coffin Cave mold beetle and a new
location for the Kretschmarr Cave mold beetle was discovered at
Stovepipe Cave. The range of the Kretschmarr Cave mold beetle has
consequently decreased since the original listing from a 45-km (28-mi)
distance in Travis and Williamson counties to a 2-km (1.2-mi) distance
in Travis County. Stovepipe Cave lies within a proposed subdivision and
the other three locations for the species, Tooth, Amber, and
Kretschmarr caves, lie within small TSNL preserves.
The Bee Creek Cave harvestman was believed to occur in five caves
in Travis and Williamson counties at the time of listing. It is
currently confirmed at four caves and tentatively identified from two
caves. The distribution of the Bee Creek Cave harvestman consists of
two disjunct areas, one about 5 km (3 mi) long and the other about 8 km
(5 mi) in length, with a distance of about 28 km (17 mi) between the
northernmost and southernmost localities, all of which lie in Travis
County. Little Bee Creek Cave, Jester Estates Cave, and Kretschmarr
Double Pit (a TSNL cave) are located in small preserve areas. Bandit
Cave is maintained as a small preserve, although attempts to relocate
the Bee Creek Cave harvestman in the cave in 1966, 1988, and 1989 were
unsuccessful (Reddell, in litt., 1993). Cave Y is located in a proposed
development area; the species' status in Bee Creek Cave is unknown
since it has not been possible to obtain permission to inspect the cave
since 1975 (Reddell, in litt., 1993).
None of these invertebrates are known to occur in large numbers
(William Elliott, Texas Memorial Museum, in litt., 1993; Reddell, in
litt. and pers. comm., 1993). The fact that several of the species are
known to occur at several dozen locations should not be interpreted to
mean that those species are abundant. (See Factor A, ``The present or
threatened destruction, modification, or curtailment of its habitat or
range,'' below).
Summary of Factors Affecting the Species
Section 4(a)(1) of the Act and its implementing regulations (50 CFR
part 424) set forth the procedures for adding species to or removing
species from the Federal Lists. A species may be determined to be an
endangered or threatened species due to one or more of the five factors
described in section 4(a)(1). These factors and their application to
the seven karst invertebrates are re-evaluated in light of new
information available to the Service and information presented in the
petition and are as follows:
A. The Present or Threatened Destruction, Modification, or Curtailment
of Its Habitat or Range
The Service determined that the primary threat to these species
comes from loss of habitat due to ongoing and proposed development
activities (final rule). The proximity of the caves inhabited by these
species to the City of Austin makes them vulnerable to continuing
expansion of the Austin metropolitan area. Threats to specific caves
occupied by these species were addressed in the final rule (53 FR
36029).
The known ranges of the Tooth Cave pseudoscorpion, the Tooth Cave
spider, the Kretschmarr Cave mold beetle, the Coffin Cave mold beetle,
and the Bee Creek Cave harvestman have not appreciably increased since
the original listing. Although the range and number of known locations
for the Tooth Cave ground beetle and the Bone Cave harvestman have
increased since the original listing, the degree of threat of habitat
destruction or modification remains significant, and may have
increased, throughout the range of each species.
Searches for karst features and karst fauna surveys have become
more frequent since the listing, as developers and landowners have
sought to comply with the Act. Many of the new locations of these karst
invertebrates have been discovered as a result of biological surveys
conducted prior to development or sale of land; consequently, newly
discovered locations are frequently threatened by habitat destruction
and other threats associated with development. The recent
revitalization of the real estate market in the Austin metropolitan
area has maintained and intensified the threat of karst invertebrate
habitat destruction and other associated threats.
The petitioners present a list of caves with endangered species
that have been subject to some degree of disturbance. They cite these
cases as demonstrating that activities such as dumping, vandalism, and
sealing of cave entrances do not actually threaten the karst
invertebrates. Reddell (in litt., 1993) counters that, in most of these
cases, the disturbance to the cave environment is recent in origin,
minor in scale, and/or generally restricted to the immediate entrance
zone. The Service concurs with Reddell and believes that these examples
do not present convincing evidence that dumping, vandalism, and sealing
entrances are harmless to the karst invertebrates. In most cases, not
enough time has elapsed since the disturbance to detect an effect on
the karst invertebrates. The Service agrees with the petitioners that
there is little quantitative data available on the direct effects of
trash dumping, vandalism, sealing, and other disturbances on the karst
invertebrates. However, there is substantial qualitative evidence
indicating that the threats to the karst invertebrates discussed in the
final rule and in this finding are real, significant, and ongoing.
Reddell (in litt., 1993) and Elliott (in litt., 1993) both cite
examples in which trash dumping, vandalism, and over-visitation have
resulted in decreased occurrence of karst invertebrates in affected
areas.
The petitioners cite the work of Crawford (1981) and Veni (1992) as
evidence that the caves where the karst invertebrates occur are not
isolated ``islands'' of special habitat and that the invertebrates
likely occur and move throughout the karst in the interstitial spaces.
In this interpretation, the petitioners misunderstand the Service's use
of the ``island'' analogy in the final rule. The final rule listing the
karst invertebrates stated that the caves containing the karst
invertebrates ``occur in isolated `islands' '' of the Edwards limestone
formation that were separated from one another when stream channels cut
through overlying limestone to lower rock layers'' (53 FR 36029). The
Service applied the island analogy to the distinct, geologically
isolated karst areas (referred to in the Draft Recovery Plan (U.S. Fish
and Wildlife Service 1993) and hereinafter as ``regions'') within which
the caves containing the karst invertebrates have formed, not to the
individual cave systems. Veni's work (1992) delineates these karst
regions and identifies areas ``having a high probability of suitable
habitat for endangered or other endemic invertebrate cave fauna.'' A
letter from Veni in response to the petition clarifies that he did not
intend that his work be interpreted to mean that there are thousands of
acres of habitat suitable for the karst invertebrates (George Veni,
Veni and Associates, in litt., 1993).
While the Service believes that the karst invertebrates are likely
to use interstitial spaces in the karst, particularly in areas with
some surface nutrient input to the karst system, the Service does not
believe that this suitable habitat exists uniformly within the larger
karst regions (as delineated by Veni (1992) and described by the
Service in the final rule as ``islands''). Finally, Crawford (1981)
focuses on aquatic karst species. In the aquatic karst ecosystems upon
which Crawford based his ideas, continuously flowing water through
caves and the interstitium may provide more continuous habitat for
aquatic subterranean species and thus provide more opportunity for
aquatic invertebrates to inhabit interstitial spaces. Given that the
Travis and Williamson County karst invertebrates are exclusively
terrestrial and that habitat for terrestrial species is more patchy and
distributed according to the occurrence of food, cover, and moisture,
Crawford's ideas may not apply to these invertebrates.
The petitioners cite the work of Curl (1966), Juberthei and Delay
(1981), and Culver (1986) as evidence that most caves have no entrance,
that caves are rare even in karst areas, and that caves may be less
favorable environments for karst invertebrates than interstitial
spaces. They cite these papers as evidence that habitat for terrestrial
troglobites (obligate cave-dwelling species) is ubiquitous in karst
areas and that the Texas karst invertebrates exist throughout the karst
even where there are no caves or openings to the surface. Culver (1986)
says that ``the number of caves (defined as cavities large enough for
human access) more or less corresponds to the number of habitable
patches for terrestrial troglobites.'' Reddell (in litt., 1993) and
Peck (1976) believe that cave entrances provide an important avenue of
nutrient input for cave fauna. Reddell (in litt., 1993) also cites
several examples in which sub-surface voids having no natural entrance
were encountered during construction activities and found not to
contain karst invertebrates. Similarly, clay-filled sinkholes with no
openings to the surface rarely contain karst invertebrates, whereas
caves and sinkholes that are sealed to human access by soil or rock
fill or with openings to the surface that allow access by cave crickets
or small mammals (and associated nutrients) more often contain karst
fauna (Reddell, in litt., 1993).
B. Overutilization for Commercial, Recreational, Scientific or
Educational Purposes
No threat from overutilization of these species is known to exist
at this time. Collection for scientific or educational purposes could
become a threat if specific localities become widely known.
C. Disease or Predation
At the time of listing, predation by and competition with non-
native species introduced in association with human habitation was
considered a potential threat to the karst invertebrates. Human
activities facilitate movement of non-native competitors and predators
such as sowbugs, cockroaches, and fire ants into an area. Buildings,
lawns, roadways, and landscaped areas provide habitat from which these
species can disperse. The relative accessibility of the shallow caves
in Travis and Williamson counties makes them especially vulnerable to
invasion by non-native species.
Fire ants are a major threat to the karst invertebrates. The
significance of this threat and the difficulty of controlling fire ants
should not be underestimated. Fire ants are voracious predators and
there is evidence that overall arthropod diversity drops in their
presence (Vinson and Sorensen 1986, Porter and Savignano 1990). Reddell
(in litt., 1993) lists at least nine cave-inhabiting species that he
has observed being preyed upon by fire ants. Elliott (1992) cites other
examples and notes that fire ant activity has increased dramatically in
Central Texas since 1989.
Although the threat posed by fire ants was not recognized at the
time these species were listed, the magnitude of the threat the ants
pose has subsequently become quite apparent. Even in the unlikely event
that fire ants do not prey upon the listed species, their presence in
and around caves could have a drastic detrimental effect on the cave
ecosystem through loss of species, inside the cave and out, that
provide nutrient input and critical links in the food chain.
Controlling fire ants once they have invaded the cave and vicinity
is difficult. Chemical control methods have some effectiveness but the
effect of these agents on non-target species is unclear. Consequently,
using chemicals to control fire ants in and near caves is not
advisable. Currently, the Service recommends only boiling water
treatment for control of fire ant colonies near caves inhabited by
listed invertebrates. This method is labor-intensive and only
moderately effective. Presently, the burden of carrying out such
practices is not a designated or mandated duty of any agency,
individual, or organization. This type of control will likely be needed
indefinitely or until a long-term method of fire ant control is
developed.
D. The Inadequacy of Existing Regulatory Mechanisms
Invertebrates are not included on the Texas Parks and Wildlife
Department's list of threatened and endangered species and are provided
no protection by the State; nor do the Department regulations contain
provisions for protecting habitat of any listed species.
As previously discussed, some of the caves containing endangered
invertebrates are in TSNL and city preserves. A small preserve
surrounds the entrance to each of these caves. However, these preserves
encompass only a fraction of the surface drainage area that provides
input of nutrients and moisture into the caves. The entire surface and
subsurface drainage area is the minimum area believed necessary to
provide adequate long-term protection for cave ecosystems. The
preserves around these caves are not sufficient to counter nutrient
depletion and prevent pollution, should the surrounding areas be
developed.
Some of the TSNL caves are under temporary deed to TSNL and may be
sold at the owner's discretion (U.S. Fish and Wildlife Service 1993).
In addition, City of Austin cave protection laws do not apply in most
cases, since the great majority of these caves lie outside the city
limits.
E. Other Natural or Manmade Factors Affecting Its Continued Existence
The Service is unaware of other threats to these species beyond
those discussed under factors A-D (above). As noted under Factor A, the
Bone Cave harvestman exhibits considerable geographical variation. Loss
of a number of locations within any one part of its range would result
in a loss of genetic diversity for the species (Reddell, in litt.,
1993). The Tooth Cave pseudoscorpion, Tooth Cave spider, Coffin Cave
and Kretschmarr Cave mold beetles, and Bee Creek Cave harvestman are
each known from fewer than 10 locations (4, 4, 5, 4, and 6 locations
respectively, including unconfirmed identifications). Therefore, the
loss of even a single location would represent a significant loss of
genetic diversity for any of those species. Lack of genetic diversity
can accelerate the decline or extinction of rare species.
Conclusion
As discussed in the final rule, these species remain extremely
vulnerable to losses. For the Tooth Cave pseudoscorpion, the Tooth Cave
spider, the Kretschmarr Cave mold beetle, the Coffin Cave mold beetle,
and the Bee Creek Cave harvestman, neither the range nor the number of
confirmed localities within the range has expanded significantly since
the original listing. The Tooth cave ground beetle and the Bone Cave
harvestman occur in more locations and are more widespread than was
originally believed, but the expansion of the overall range is not
significant and the majority of caves in which these species occur are
subject to one or more of the threats discussed above (Reddell, in
litt., 1993).
The Service recently released a Draft Recovery Plan for the karst
invertebrates (U.S. Fish and Wildlife Service 1993). That document
details recovery actions and criteria that, when met, may result in
reclassification or delisting of the endangered karst invertebrates.
Continued efforts to locate new inhabited caves, to implement habitat
conservation measures, and to control the threat of fire ants could
bring the karst invertebrates to the point where protection under the
Act is no longer necessary.
The Service has carefully assessed the information presented in the
petition, as well as the best and most current scientific and
commercial information, in determining that the petition does not
present substantial scientific and commercial information indicating
that delisting of any of the seven karst invertebrates may be
warranted. These species continue to require the protection provided by
the Act because of their extremely small, vulnerable, and limited
habitats located within an area that is experiencing continued
pressures from economic and population growth.
References Cited
Brignoli, P.M. 1977. Spiders from Mexico. III. A new leptonetid from
Oaxaca (Araneae, Leptonetidae). Acad. Naz. Lincei, Probl. Att. Sci.
Cult., 171(3): 213-218.
Chandler, D.S. 1992. The Pselaphidae of Texas caves (Coleoptera).
Pages 241-254 in: Texas Memorial Museum Speleological Monographs 3:
Studies on the cave and endogean fauna of North America II. Edited
by James Reddell. 257 pp.
Crawford, R.L. 1981. A critique of the analogy of caves and islands.
Proc. Eighth Intl. Cong. of Speleol. 1:295-297.
Culver, D.C. 1986. Cave Faunas. Pages 427-443 in: Conservation
Biology: The science of scarcity and diversity. M.F. Soule (ed.).
Sinauer Associates, Sunderland, MA. 584 pp.
Curl, R.L. 1966. Caves as a measure of karst. J. of Geology 74:798-
830.
Elliott, W.R. 1992 (rev. 1993). Fire Ants and Endangered Cave
Invertebrates: A Control and Ecological Study. Section 6 report
prepared for the Texas Parks and Wildlife Department and the U.S.
Fish and Wildlife Service.
Juberthei, C., and B. Delay. 1981. Ecological and biological
implications of the existence of a ``superficial underground
compartment.'' Proc. Eighth Intl. Cong. of Speleol. 1:203-206.
Muchmore, W.B. 1992. Cavernicolous pseudoscorpions from Texas and
New Mexico (Arachnida:Pseudoscorpionida). Pages 127-154 in: Texas
Memorial Museum Speleological Monographs 3: Studies on the cave and
endogean fauna of North America II. Edited by James Reddell. 257 pp.
Peck, S.B. 1976. The effect of cave entrance on the distribution of
cave-inhabiting terrestrial arthropods. Int. J. Speleol. 8:309-321.
Platnick, N.I. 1986. On the tibial and patellar glands,
relationships, and American genera of the spider family Leptonetidae
(Arachnida, Araneae). Amer. Mus. Novit., 2855. 16 pp.
Porter, S.D., and S.A. Savignano. 1990. Invasion of polygyne fire
ants decimates native ants and disrupts arthropod community. Ecology
71(6):2095-2106.
Ubick, D., and T.S. Briggs. 1992. The harvestman family
Phalangodidae. 3. Revision of Texella Goodnight and Goodnight. Pages
155-240 in: Texas Memorial Museum Speleological Monographs 3:
Studies on the cave and endogean fauna of North America II. Edited
by James Reddell. 257 pp.
U.S. Fish and Wildlife Service. 1993. Draft Recovery Plan for
Endangered Karst Invertebrates in Travis and Williamson Counties,
Texas. Albuquerque, New Mexico. 133 pp.
Veni and Associates. 1992. Geologic controls on cave development and
the distribution of cave fauna in the Austin, Texas, region.
Prepared for the U.S. Fish and Wildlife Service. v + 77 pp.
Vinson, S.B., and A.A. Sorensen. 1986. Imported Fire Ants: Life
history and impact. Texas Dept. of Agriculture 1986. 28 pp.
Author
The primary author of this notice is Ruth Stanford (See ADDRESSES
section).
Authority
The authority for this action is the Endangered Species Act of
1973, as amended (16 U.S.C. 1531-1544).
List of Subjects in 50 CFR Part 17
Endangered and threatened species, Exports, Imports, Reporting and
recordkeeping requirements, and Transportation.
Dated: March 7, 1994.
Mollie H. Beattie,
Director, Fish and Wildlife Service.
[FR Doc. 94-5854 Filed 3-11-94; 8:45 am]
BILLING CODE 4310-55-P