194 GEO. H. HORN, M. D. 



C OTiponnis, ITorn. 



Clypeus broadly rounded. Antenna) eight-jointed. Elytra oval, 

 humeri obliterated, wings entirely wanting. 



TRICHIUS, Fab. 



The sexual characters of the species require primary attention. 

 The pygidium of the male is always more convex than that of the 

 female, and the tip somewhat inflexed. This affords the means of 

 distinguishing the sexes at all times. 



In delta the males have the anterior tibiiv; bidontatc, in the female 

 tridentate, the anterior tibial spur is less developed in the male, and 

 the hind tibiEC of the same sex have a small obtuse tooth at the middle 

 of the inner side. The middle of the posterior margin of the fourth 

 ventral segment is elevated in the male and flat in the other sex. 

 This species has been separated by Burmeister, and with its congeners 

 named Triijonopeltastcs. The tibial differences in the sexes form the 

 characters of the genus which may for convenience be continued. 



The other species of Trichius have the tibiae similar in their denta- 

 tion in the sexes. T.pi<jer and texanus have no anterior tibial spur in 

 the jnale, while it is always present iu the males of the other species, 

 although much feebler in the males than in the females. 



In bibens and viridulus the females have the pygidium sinuate ou 

 each side near the tip, the tip being truncate. This sinuation is 

 hardly observable in the males. 



These characters reduced to the tabular form give the following 

 result : 



Anterior tibise similarly dentate in the sexes. (Triciiiu.s.) 

 Anterior tibiae % without spur. 



Body beneath and pygidium rufous; anterior tibite % moderately stout. 



pigcr. 

 Body beneath and pygidium black; anterior tibise % with inner edge very 



broad texanu!«. 



Anterior tibite % with spur, more slender and straight than in the 9 • 

 Pygidium oval at tip in both sexes. Elytra with lateral velvety space. 

 Third and fifth elytral intervals subcostiform ; two oblique white fascire. 



atlinis. 

 Pygidium sinuate on each side and truncate at tip. Elytra without lateral 

 velvety space, intervals equal. 



Elytra orange red with tinge of seneous bibcnM. 



Surface brilliant metallic green viridulus. 



Anterior tibire dissimilarly dentate in the sexes. (Trigonopeltastes.) 



Thorax with reversed deltoid mark delta. 



T. pigcr. Fab.— Head and thorax densely punctulate, sparsely clothed with 

 short, yellowish, erect hairs, surface slightly tinged with green. Elytra rufous 



