Chap. X. 
COLEOPTEEA. 
367 
habitually frequent. Other species are ornamented 
with gorgeous metallic tints, — for instance, many Cara- 
bidte, which lire 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 0. 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 he 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 he that blind insects inhabit caves 
and other obscure stations. 
Some ' Longicorns, however, especially certain Pri- 
onidrn, 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. 1 he males in 
the genus Pyrodes, 58 as I saw in Mr. Bates collection, are 
58 Pyrodes pulcherrimus, in which tlie sexes differ conspicuously, has 
been described by Mr. Bates in ‘ Transact. Eut. Soc.’ 1809, p. 50. I 
WiU specify tiro few other cases in which T have heard oi a difference 
>n colour between the sexes of beetles. Kirby and , Spence (‘ Introduct. 
to Entomology,’ vol. iii. p. 301) mention a Cantharis, Mcloe, Rhagium, 
and the Leptura testacea ; the male of tiro latter being testaceous, with 
a black thorax, and the female ot a dull red all over. These two 
tatter beetles belong to the Order of Longicorns. Messrs. It. Trimen 
and Waterhouse, junr., inform mo of two Lamellicorns, viz., a Peri- 
