CERAMBYCIDAE. 289 



edge of the hind femora, which are flattened and sulcate beneath. 

 The legs are slender, compressed, and punctate. 



The sexual characters are obvious in the antenna, heavy in 

 the , slender in the ? . In some of the species the abdomen 

 in the last-named sex is enlarged, and the -mtercoxal process is 

 so broad as to show that the character possesses not even a 

 generic value ; the division Prioni subterranei of Lacordaire 

 has therefore no foundation in nature, and its contents should be 

 distributed according to the affinities of the individual genera. 

 The 5th ventral segment in the is truncate and broadly emar- 

 giuate, so that the 6th is visible ; in the <? it is more elongate, 

 gradually narrowed behind and truncate, and the 6th segment 

 is not exposed. 



Our genera are but two in number, Prionus, containing several 

 species, occurs in every part of the country ; Homaasthesis (P. 

 integer Lee., emarginatus Say) found in Colorado and New 

 Mexico. P. innocuus Lee. is the female of one of these species, 

 probably emarginatus; the hind coxae are very widely separated, 

 and the intercoxal process of the 1st ventral segment is very 

 short and wide. 



There is much difference in the soles of the hind tarsi, which 

 sometimes, as in P. brevicornis, are as thickly clothed with hair 

 as the other feet and marked with a narrow medial groove ; 

 sometimes, as in P. palparis and Homaesthesis, flattened or broadly 

 concave and nearly naked ; sometimes again, as in P. fissicornis 

 and imbricornis, the covering of hair is thin, so that the joints 

 appear punctured, with a narrow smooth medial groove. 



We see, therefore, in this genus that structural characters 

 assume a merely specific importance, a fact which must be con- 

 stantly borne in mind in attempting a rational classification of 

 Oerambycidas. 



Tribe V. TR A CiOSOlHIM. 



This tribe is represented in our fauna by Tragosoma Harrisii, 

 which scarcely differs from the North European T. depsarium; 

 it occurs from Newfoundland to Vancouver Island, but is not 

 abundant. The body is elongate (30-35 mim. long) ; the prothorax 

 alike in both sexes, very hairy, and armed on the side with a 

 single acute tooth. The elytra are punctured and finely ribbed. 



The poriferous system of the antennas of the 9, which are 



