Chap. X. COLEOPTERA. 367 



habitually frequent. Other species are ornamented 

 with gorgeous metallic tints, — for instance, many Cara- 

 bidae, which live on the ground and have the power 

 of defending themselves by an intensely acrid secretion, 

 — the splendid diamond-beetles which are protected by 

 an extremely hard covering, — many species of Chry- 

 somela, such as C. cerealis, a large species beautifully 

 striped with various colours, and in Britain confined 

 to the bare summit of Snowdon, — and a host of other 

 species. These splendid colours, which are often 

 arranged in stripes, spots, crosses and other elegant 

 patterns, can hardly be beneficial, as a protection, except 

 in the case of some flower-feeding species; and we 

 cannot believe that they are purposeless. Hence the 

 suspicion arises, that they serve as a sexual attraction ; 

 but we have no evidence on this head, for the sexes 

 rarely differ in colour. Blind beetles, which cannot of 

 course behold each other's beauty, never exhibit, as I 

 hear from Mr. Waterhouse, jun., bright colours, though 

 they often have polished coats : but the explanation of 

 their obscurity may be that blind insects inhabit caves 

 and other obscure stations. 



Some Longicorns, however, especially certain Pri- 

 onidte, offer an exception to the common rule that the 

 sexes of beetles do not differ in colour. Most of these 

 insects are large and splendidly coloured. The males in 

 the genus Pyrodes, 58 as I saw in Mr. Bates' collection, are 



53 Pyrodes pulcherriinus, in which the sexes differ conspicuously, has 

 been described by Mr. Bates in ' Transact. Ent. Soc' 1869, p. 50. I 

 will specify the few other cases in -which I have heard of a difference 

 in colour between the sexes of beetles. Kirby and Spence (' Introduct. 

 to Entomology,' vol. iii. p. 301) mention a Cantharis, Meloe, Rhagium, 

 and the Leptura testacca ; 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 Order of Longicorns. Messrs. R. Trimen 

 and Waterhouse, junr., inform me of two Lamellicorns, viz., a Peri- 





