276 GEO. H. HORN, M. D. 



above. Labium truncate. Eyes oval, convex, entire. Maxillary 

 palpi rather .slender, i^econd joint cylindrical, third obconical, fourth 

 more slender, conical and acute at tip. Antenni:e always longer than 

 half the body, often nearly as long, slightly stouter at tip. Protho- 

 rax broader than long, not, or only apparently narrowed in front, 

 sides arcuate, often oblique at the front angles, base arcuate, but 

 sometimes feebly so. Elytra oval or ol)long, usually convex, the 

 humeri variable, sometimes entirely obliterated in the apterous spe- 

 cies, surface variably punctate, but always in a confused manner. 

 Prosternum narrow, slightly dilated behind, the coxal cavities broadly 

 open. Legs moderately long. Posterior thighs robust and often 

 attaining the apices of the elytra. Tibi^ as long as the femora, 

 dilated toward the apex, the posterior broadly grooved on the outer 

 edge and finely denticulate, terminated by a long curved spur. 

 Tarsi slender, the first joint of the posterior pair nearly or fully 

 half the length of the tibia and as long as all the following joints 

 united (PI. VII, fig. 14). Abdomen with five free ventral segments. 



An important modification of the definition of the genus as given 

 by Chapuis must be made in reference to the structure of the an- 

 tennae. The fourth joint is not always longer than the third, as a 

 considerable number of our species have the joints 2-3-4 very nearly 

 equal in length. This has affi^xled an important means of dividing 

 the genus primarily as will be seen in the table. The other charac- 

 ters are sufficiently plain, and will not require special comment. It 

 must, however, be observed that the colors are slightly variable, and 

 the consequent determination of unique examples is attended with 

 more or less uncertainty. 



The sexual characters have been observed and recorded in several 

 species. In nearly all the males have the first tarsal joint of the 

 front and often the middle legs longer and broader than in the 

 female. The last ventral of the male varies in its characters, and is 

 sometimes sinuate each .side with a median inq^ressed lobe as in 8ys- 

 tena, or again subtruncate with a slight longitudinal inqjression, or 

 finally, simply more convex than in the female. The antennte are 

 often longer and stouter in the male ; the sutural angle of the elytra 

 in several species is more distinct in the male, broadly I'ounded in 

 the female. 



The genus is an extremely difficult one to deal with, certainly 

 more so than any other Halticini of our fauna, and the attenq)ts to 

 reduce the species to some .sort of tabular order has not been very 



