428 TERTIARY INSECTS OF NORTH AMERICA. 



ency to a transverse arrangement into corrugations. Antennae more than 

 half as long as the body, slender, and pale, the whole body being black or 

 blackish fuscous. Thorax trapezoidal, broader than long, as long as the head, 

 tapering regularly and considerably in front, the apical margin being about 

 three-fourths the length of the base ; surface coarsely granulate. Hemelytra 

 with the corium and clavus blackish fuliginous, the former just before the 

 middle with a large triangular pallid spot on the costal margin sending from 

 its apex a curved pallid shoot to the membranal margin; membrane pale 

 fuliginous with a large trapezoidal pallid spot next the apex of the corium on 

 the costal margin ; veins marked in fuscous. Legs dark fuliginous, the hind 

 pair very slender, the hind femora nearly as long as the abdomen, the hind 

 tibia; delicately and profusely spinous. 



Length, 6.5-8.5 mra ; average about 8 mm . 



This is the commonest of the heteropterous insects of Florissant. 



Florissant. About one hundred and fifty specimens, of which some of 

 the best are Nos. 2431, 3257, 56G9, 7102, 8374, 9045, 9170, 11211, 11217, 

 12081, 12087, and of the Princeton collection, 1.335 and 1.712. 



4. RHEPOCORIS PROPINQUANS. 



PI. 25, Fig. 1 ; PI. 26, Fig. 13. 



In studying the species of Rhepocoris I discovered that they were 

 naturally subdivided into three groups according to their size, and that it was 

 not often that there was any doubt into which of the three groups any given 

 individual would fall. I have accordingly separated the present species 

 from those on either side of it, though I can give no characters at all except 

 those of size. In a few instances there may be doubt into which of the two 

 species, this and the preceding, any given individual may fall, inasmuch as 

 the range of form comes close together, and it may be that these two should 

 be considered as one and the same species. But I have thought it best 

 under the circumstances, and in the hope of being able by more careful 

 study to separate the forms on other characteristics than that of mere size, 

 to keep the two apart, at least provisionally. In each of these two forms 

 the individuals may be separated as slenderer and stouter, which I regard 

 as probably the two sexes, as they seem to differ in no other constant char- 

 acter that can be seen in their state of preservation. 



