32 Trans. Acad. Sci. of St. Louis. 



diminishes in less developed males and is completely obsolete 

 in others, leaving only the peculiar discal foveae or short 

 transverse setose folds of the second and third segments. 

 The female has the abdomen entirely unmodified as a rule, 

 but in hacUum, Mcolor, x>arallelum and some others, the dis- 

 cal mark of the second segment — a fovea in some or a trans- 

 verse fold in others — seems to remain in that sex. The sixth 

 ventral of the male is obtusely rounded at tip or subtruncate. 

 Gatitrolobium differs very much from CryptoUum, under 

 which name all the species have been described thus far, in 

 structure and habitus. The species represented in my cabinet 

 may be identified as follows : — 



Head parallel, inflated or moderately narrowed behind the eyes, the basal 

 angles always more or less evident and broadly rounded 2 



Head gradually narrowed behind the eyes, the sides converging from the 

 latter to the neck and evenly, feebly arcuate throughout, the basal angles 

 wholly obsolete 24 



2 — Elytral punctures close-set, never more thau feebly and partially serial 



in arrangement ^ 



Elytral punctures sparse, very coar.-<e, arrani?ed in even series 23 



3 _ Elytra generally pale, rarely black, never pale at tip 4 



Elytra black, with a fine, abruptly pile testaceous apical margin. ....22 



4— Prouotum highly polished, without minute ground sculpture of any 



kind. 



5 



Pronotum alutaceous in lustre, the dullness caused by excessive y minute 

 close-set and regular punctulation, only distinct under comparatively 



high amplification 21 



5— Head black or piceous-black in color 6 



Head pale and concolorous with the prothorax and elytra 16 



6 _ Prothorax black or piceous-black in color 7 



Prothorax paler in color and generally concolorous with the elytra 9 



7 _ Head parallel and straight at the sides for one and one-half times the 



length of the eye behind the latter, the sides thence broadly rounded to 

 the neck. Body moderately large and stout, deep black throughout, the 

 abdomen feebly rufo-picesceat; legs very pale, the antennae dusky; 

 head longer than wide, narrower than the elytra in the female, coarsely, 

 closely punctate, the ridge between the post-ocular foveae very pro- 

 nounced; prothorax oblong-elongate, parallel, with the sides nearly 

 straight, much narrower than the head, the punctures unusually coarse, 

 moderately sparse; elytra slightly elongate, two-fifths wider and 

 nearly a third longer than the prothorax, parallel, the sides straight, 



abdomen the reader is referred to some remarks upon this subject published 

 many years ago by the writer (Bull. Cal. Acad. Sci., II, 1886, p. 159 and 

 plate) . 



