24 John Todd Zimmer 



of the ciliae and comb-teeth on the juga of this species but I have 

 found these characters too variable to be formulated. Their 

 number and arrangement is not constant, even on opposite juga 

 of the same insect. 



Genus Pangaeus Stal 

 Pangaeus bilineatus (Say). 



1825. Cydniis bilineatus Say, Journ. Acad. Phil., IV, p. 315. 



A rather large series of this species is present from Lincoln, 

 collected from June to September. Other specimens are labeled 

 " Roca " and " Southeast Nebraska " and I have seen specimens 

 from Sterling, where they were reported as injuring wheat. 



Genus Geotomus Mulsant & Rey 

 Geotomus robustus (Uhler). 



1877. Melanaethus robustus Uhler, Bull. U. S. Geol. Geog. Surv., Ill, 

 No. 2, p. 390. 



I have a female from Lincoln, as well as a pair from Wash- 

 ington, D. C, and I have seen a male taken also at Lincoln which 

 I must refer to this species at least temporarily, although I be- 

 lieve that they are distinct from it. They differ in shape and 

 in the posterior marginal bristles as nearly as I can make out 

 from the description of Uhler's and the figures given by Signoret, 

 but tmtil I have a larger series of specimens belonging to this 

 genus, including some undoubted rohustiis, it will perhaps be best 

 to consider the insects at hand under this head. 



Genus Amnestus Dallas 



KEY TO THE SPECIES 



I. Size larger (length, 4 mm) ; form somewhat more convex and color 



darker spinifrons 



I. Size smaller (length, 2.75 mm) ; form less convex and color paler 2 



2. Juga, each with five comb-teeth; anterior femora, sometimes at 



least, with large bifid tooth pallidus 



2. Juga, each with only four comb-teeth ; anterior femora without 

 tooth pusillus 



242 



