No. 34-] HEMIPTERA OF CONNECTICUT I CYDNIDAE. 779 



Key to Tribes. 



Front tibiae broad and flat Cydnini 



Front tibiae cylindrical, dilated apically Sehirini 



Tribe CYDNINI. 



Species of black or rarely brown color living for the most part 

 in the ground, under stones and in ant nests. The tibiae are 

 thickly set with strong spines and long setae, inserted irregularly 

 over the entire surface except on the front legs where the tibiae 

 are flattened and the spines confined largely to the anterior edge 

 and broad apex of the segment. These structures, and the entire 

 ventral aspect of the insects in a general way, recall very strongly 

 the corresponding parts as developed in the Histerid beetles, the 

 apparent convergence extending even to the mode of attachment 

 of the spines, which, in the Cydnines, are not continuous with the 

 tibial surface but are set into cup-like elevations, after the manner 

 of the "inserted denticles" of the beetles. This similarity in struc- 

 ture may perhaps have arisen in connection with the similarity in 

 habits of many of the species, which in both groups are more or 

 less subterranean and myrmecophilous. But our knowledge of 

 these most mysterious Hemiptera is very incomplete and further 

 observations on their modes of life will be of the greatest interest. 

 The species of this tribe are characteristically southern in 

 distribution and they are rarely to be met with in New England. 



Key to Genera. 



1. Margin of head toothed ; color brown Amnestus 



Margin of head entire ; color black 2 



2. Pronotum with an impressed line along anterior margin Pangaeus 



Pronotum without impressed line Geotomus 



Pangaeus Stal. 



Head almost flat, anterior margins broadly rounded, narrowly 

 reflexed ; metasternal orifices with a narrow somewhat irregular 

 canal. Anterior tibiae broadly flattened. Form oval, the margins 

 ciliate with strong sparse setae. One species is reported from our 

 territory. 

 P. bilineatus (Say). 



Jour. Acad. Nat. Sci. Phila., 10, 1832. 



Black, shining, antennae and rostrum paler. Length 6.5-7.5 "^^n- 



Known to occur in New England only from Massachusetts and 

 Connecticut records given by Uhler. 



Geotomus Mulsant and Rey. 



Head broadly rounded anteriorly, margins ciliate and narrowly 

 reflexed ; orificial canal broadly rounded at apex. Anterior tibiae 

 moderately flattened. Form oval, margins ciliate. 



