632 NORTH AMERICAN ASTACID®—FAXON. 
Labette County, Kansas. W.S. Newlon(M.C.Z.). Five males, form 
I; five males, form II; seven females. 
This species much resembles C. virilis, especially the form called 
variety A by Dr. Hagen. It differs in the shape of the first abdominal 
appendages of the male. In C. nais the rami of these appendages are 
shorter and more strongly curved than in C. virilis, but not so much 
curved as in C. immunis. The areola is narrower than in C. virilis. 
The first abdominal appendages are very like those of C. palmeri Fax., 
as far as can be seen by a comparison of the second-form males alone; 
but the areola is not obliterated in any part of its course ip C. nais 
and the rostrum is more tapering than in C. palmeri. 
Cambarus immunis Hag. 
Additional localities: Wabash River, New Harmony, Indiana, D. 8S. 
Jordan (U.S. F. C.); Lafayette, Indiana, H. L. Osborn (M. C. Z.). 
Cambarus immunis spinirostris Fax. 
Additional locality: Ward’s Creek, Shawnee County, Kansas. F, 
W. Cragin and J. B. Fields (M. C. Z.). 
When I described this variety in 1884, I had not seen the first form 
of the male, which is included among the specimens collected by Messrs. 
Cragin and Fields. The lateral spines of the rostrum are distinct, as 
in the second-form male and in the female; the sete on the second pair 
of legs are well developed; the first abdominal appendages are shaped 
exactly as in the first-form male of the typical C. immunis. 
Cambarus rusticus Gir. 
Additional localities: Maramee River, Dent County, Missouri, R. E. 
Call (M. C. Z.); Harpeth River, Franklin, Tennessee, Gilbert and 
Swan (U.S. N. M.); Osage River, La Cygne, Kansas (M.C. Z.). All 
these are similar to the form placidus Hag. 
Cambarus spinosus Bundy. 
Additional locality: Tar River Rocky Mount, North Carolina. D.S. 
Jordan (U.S. F. C.). 
Cambarus hylas, sp. nov. 
Male, form II.—Rostrum broad, excavated, margins thickened, some- 
what convergent from the base to the acute lateral spines; acumen of 
moderate length. Post-orbital ridges ending anteriorly in an acute 
spine ; carapace punctate, with a small lateral and a branchiostegian 
spine; antero-lateral margin notched but not furnished with a sub- 
orbital spine; posterior segment equal in length to half the distance 
from the end of the rostrum to the cervical groove; areo'a of moderate 
width, punctate. Abdomen longer than the cephalothorax ; basal seg- 
ment of the telson bispinous on each side of the posterior border. 
