S86 



TEE DESCENT OF MAN 



beetles, whicli cannot, of course, beliold each other's beauty, 

 never, as I hear from Mr. "Waterhouse, Jr., exhibit bright 

 colors, though they often have polished coats; but the 

 explanation of their obscurity may be that they generally 

 inhabit caves and other obscure stations. 



Some Longicorns, especially certain Prionidae, offer an 

 exception to the rule that the sexes of beetles do not differ 



Fio. 16.— Ohalcosoma atlas, 



female (natural size). 



Upper figure, male (reduced); lower figure, 



,ie 



in color. Most of these insects are large and splendidly 

 colored. The males in the genus Pyrodes," which I saw 

 in Mr. Bates's collection, are generally redder but rather 



" Pyrodes pulcherrimus, in wMch the sexea differ conspicuously, has been 

 described by Mr. Bates in "Transact. Bnt. Soc," 1869, p. 50. I will specify 

 the few other cases in which I hare heard of a difference in color between the 

 sexes of beetles. Kirby and Spence ("Introduct. to Entomology," vol. iii. p. 

 301) mention a Cantharia, Meloe, Ehagium, and the Lepiitra iestacea ; the male 

 of the latter being testaceous, with a black thorax, and the female of a dull red 

 all over. These two latter beetles belong to the family of Longicorns. Messrs. 

 E. Trimen and Waterhouse, Jr., inform me of two Lamellicorns, viz., a Peri- 

 triohia and Trichius, the male of the latter being more obscurely colored than 

 the female. In KUus ehngatws the male is black, and the female always, as it 

 is believed, of a dark-blue color, with a red thorax. The male, also, of Orso- 

 dacna atra, as I hear from Mr. Walsh, is black, the female (the so-called 

 O. TvificoUis) having a' rufous thorax. 



