CRAYFISHES OF NEBRASKA AND EASTERN COLORADO 
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CAMBARUS (FAXONIUS) VIRILIS HAGEN 
Cambarus virilis, Hagen, 1870, p. 63; Forbes, 1876, pp. 4 and 19; Bundy, 1877, p. 171; Herrick, 1882, p. 253; Faxon, 1885, p. 147; Faxon 
1885a, p. 96; Hay, 1896, p. 499; Pearse, 1910, p. 17. 
Cambarus ( Faxonius ) virilis, Ortmann, 1905a, pp. 112-113. 
Male, Form I. 
Body long, not very robust; rostrum broad, long, well excavated, with raised 
margins, lateral teeth prominent and acute; acumen long, slender, terminal spine 
sharp ; post-orbital ridges grooved on outer edge, slightly swollen posteriorly, having 
an acute spine anteriorly; carapace cylindrical, pitted dorsally, granulate laterally; 
lateral spine on cervical groove; cervical groove deep, broken; areola of moderate 
width, posterior triangle much longer than anterior; chela strong, thickly punctuate, 
tips of fingers equal, decurved, horny, with small tubercles on cutting edges of both 
fingers, immovable finger pubescent; third pair of periopods hooked; first pair of 
abdominal appendages very long, reaching nearly to the base of second periopods, 
bifid, falciform, the external branch longer, with recurved chitinous tip, inner branch 
recurved, flattened and spatulate at tip. 
Colorado localities. — South Platte River, near Julesberg, Sedgwick County; 
Republican River, Wray, Yuma County; St. Charles River, tributary of the Arkan- 
sas River near Pueblo, Pueblo County. 
Nebraska localities. — Blue River, Milford, Seward County; creek 6 miles south 
of Grand Island, Hall County; Louisville (collected by Theodore Stander). 
CAMBARUS (FAXONIUS) IMMUNIS HAGEN 
Cambarus immunis, Hagen, 1870, p. 71; Forbes, 1876, pp. 4 and 19; Bundy, 1877, p. 171; Pearse, 1910, p. 81. 
Cambarus signifer, Herrick, 1882, p. 253. 
Cambarus ( Faxonius ) immunis, Ortmann, 1905a, p. 113. 
Form I. 
Body slender; rostrum broad at base, well excavated, very slightly decurved, 
margins raised, converging; no marginal spines; acumen blunt, with concave sides; 
post-orbital ridges grooved on lateral face, without spines; carapace smooth, flat- 
tened dorsally, granulate laterally; lateral spine small, cervical groove deep, broken; 
areola narrow in middle, anterior triangle small and indistinct, posterior triangle 
larger, not distinct; chela long and tapering, internal finger deeply excised at base, 
immovable finger heavily bearded; second periopods with dense tufts of hair on 
inner side of distal segments ; third periopods hooked ; first pair abdominal append- 
ages reaching nearly to the base of second periopods, falciform, bifid, external branch 
longer, with strongly recurved chitinous tip, inner branch recurved, flattened, and 
spatulate. 
Colorado localities. — Denver, Denver County; Dry Creek, near Boulder, Boulder 
County; St. Vrains, Weld County; Greeley, Weld County; Empire Reservoir, near 
Deerfield, Weld County; Fort Collins, Larimer County; Louisville Junction, Boulder 
County; Allens Lake, Boulder County; Castle Rock, Douglas County. 
Nebraska localities. — Lincoln, Lancaster County, many vicinities; Grand Island, 
Hall County; State fisheries, Sarpy County; Seward, Seward County; Hanlon, 
Lancaster County; Humboldt, Richardson County, sent by Irving Moore; Cass 
County; Richardson County, sent by Theodore Stander; Atkinson, Holt County; 
Pleasantdale, Seward County; Havelock, Lancaster County; Roca, Lancaster 
County. 
