Chap. X. 
COLEOPTERA. 
3(37 
habitually frequent. Other species are ornamented 
with gorgeous metallic tints, — for instance, many Cara- 
bidoe, 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- 
onidae, 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 
58 Py r odes pulcherrimus, 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 (‘ Introduce, 
to Entomology/ vol. iii. p. 301) mention a Cantharis, Meloe, Rhagium, 
and the Leptura testacea ; 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- 
