130 GEO. H, HORN, M. D. 



ACAKTIIOCINUS Steph. 



This genus reproduces the characters of Urograplils in great part 

 but differs in the following : 



Antennae one-half longer than the body 9 , three times as long in 

 the % or even longer, joints 3 — 4 and in some the next two hairy 

 beneath. Thorax with a moderately strong spine at the side a little 

 behind the middle. Elytra without erect hairs, clothed with the 

 usual recumbent pubescence. 



The males have an additional, exsert, dorsal, abdominal segment, 

 valve-like, broader at tip and emarginate, the normal fifth segment is 

 triangularly emarginate as in the other genera of this group. This 

 additional segment is less exsert in 7iodosus. In the other two genera 

 the segment may be seen but is always retracted. 



The antennae of the male present two forms, the one in which 

 the joints are simple, the other with the fourth (piodos^is), or fifth 

 {spectahilis), joint dilated within at its tip. In the female the joints 

 3 — 11 are nearly equal in length but there is a great variation in the 

 males. In some of the latter, althaugh the antennae may be much 

 longer than the body, the joints 3 — 11 are also nearly equal, but 

 in others, particularly those with very long antennae, the four outer 

 joints are much longer. This is especially observable in nodosus 

 and spectahilis. 



As already observed by Dr. Leconte our species seem to tend 

 toward Eatrypanus. In fact one of them has been re-described under 

 that name. 



Our species are four in number and separate very easily in the 

 following manner : 



Elytra punctured beyond the middle. Antennae of % not nodose. 



Elytra not distinctly costulate obsoletus Oliv. 



Elytra distinctly tricostulate obliquus Lee. 



Elytra scarcely at all punctured beyond the middle. Antennae '^ nodose. 

 Elytra coarsely punctured at base, surface with three dark oblique bands. 



spectabilis Lee. 

 Elytra feebly punctured at base, surface with linear and arrow-shaped 



velvety spaces nodosus Fab. 



The first two are smaller species, the last two large. 

 Their distribution is as follows : 



A. OBSOLETUS widely distributed in the northern part of the 

 Atlantic region. 



A. NODOSUS, Middle States to Florida. 



A. OBLIQUUS, Kansas, New Mexico, Utah and California. 



A. SPECTABiLis, New Mexico to Oregon and Vancouver. 



