92 AMERICAN COLEOPTERA. 



tor ( 9 ) the last ventral is finely punctate and bristling with 

 short erect black hairs. This character, which seems to have 

 escaped notice hitherto, may be relied upon to separate pere- 

 grinator from all allied forms. 



C. tristoides n. sp. 



This name is proposed for a form occurring in our extreme 

 southwestern region, which is closely related to but quite 

 surely distinct from triste of the West Central States. As 

 compared with Kansas specimens of triste in my collection, 

 tristoides differs in the much finer punctures of the elytral 

 series, these becoming very minute posteriorly, and in the 

 usually well developed greenish lustre of the elytral margins. 

 The sides and basal impressions of the prothorax also show 

 more or less of the metallic lustre in many specimens, but in 

 some it is barely perceptible. The coarser serial punctures 

 of intervals 4, 8, 12 are green as in triste, but in the latter 

 species the side margins of the body are scarcely at all so. 

 In the type series of three examples of triste in the LeConte 

 collection the sides of the prothorax are evenly rounded and 

 the elytra are parallel in both sexes. In tristoides the pro- 

 thorax exhibits considerable inconstancy in both relative and 

 actual dimensions, the width varying from 1.53 to 1.72 times 

 the length, the sides either evenly rounded or evidently 

 straighter posteriorly, ; the basal sinuations are also variable 

 in depth. The elytra are quite uniformly parallel in the male 

 and a little wider posteriorly in the female. It is, however, 

 very probable that a good series of triste, or for that matter 

 of any other species of Calosoma, would show similar vari- 

 ability. In length tristoides ranges from 22 to 24 mm., width 

 9.4-10.2 mm. The length given for triste in LeConte's table 

 is 18 mm. 



Tristoides is based on a good series taken by Mr. Rick- 

 secker at or near San Diego, California. 



A single specimen from an unknown source and simply 

 labeled " Cal. " has stood for years in my collection as triste. 

 There is a single example from " Cal. " in the LeConte col- 

 lection placed near but not in line with his specimens of 

 triste and bearing a " ? " label. 



