/ 
1864.] 551 
moderately curved, lurid yellow, piceous at tip; cerci of the female 
hardly longer than the segment beneath which they are placed; no 
cerci present in the males, but their place is supplied by short, stout 
cylindrical appendages which are bifurcated at tip, the branches acute 
and curved inwardly, the inferior branch being much longer and taper¬ 
ing more to the tip than the superior one. Legs, in the fully colored 
specimens, deep purplish-brown, mottled with yellow upon the anterior 
femora, and reticulated with yellow on the exterior side of the posterior 
femora; posterior legs comparatively short, the spines tipped with black; 
the denticuloid process above the anterior coxae triangular at base, 
acute at tip, about as long as the coxa; the legs in pale specimens are 
largely pervaded with yellow. 
Length to tip of last segment % . 32—33^ millims. Length of pro¬ 
thorax 11 millims., breadth at apex 7 millims. Posterior femur 18^ 
millims. 9 Length to tip of last segment 34—36 millims. Posterior 
femur 18—19 millims. Ovipositor 20—21 millims. 
Hab. Minnesota (Kennicott) ; Washington Territory (Dr. Suckley) ; 
Texas (Dr. Horn). 
This species was found by Mr. Robert Kennicott in considerable 
numbers near the Red River in Northern Minnesota; for the specimens 
examined and here described I am indebted to his generosity. From 
all the species previously described it differs in many particulars from 
the characters given by the describers. It seems to approach the most 
nearly to A. simplex, Hald., in the shape of the limbs, &c., but the 
markings are widely distinct. 
For the distinctness of this genus from Thijyxonotus, Serv., I can by 
no means vouch; a sufficient examination of all the species hereafter 
may render it necessary to unite them into one genus. The measure¬ 
ments given are the result of an examination of twenty specimens of 
both sexes. 
CYPHODERKIS, nov. gen. 
Form short, robust. Head globose superiorly, deeply inserted into 
the prothorax, very wide and flat between the antennae; eyes subglo- 
bose, placed rather before the sides, immediately exterior to the sock¬ 
ets of the antennae; antennae longer than the body, scarcely attenuated 
at tip, being almost of equal thickness throughout, basal joint long, 
stout, cylindrical, the second scarcely more than half as thick, and less 
