Chap. X. 
DIPTERA AND HEMIPTERA. 
349 
is in the genus Bibio, in which the males are blackish 
or quite black, and the females obscure brownish-orange. 
The genus Elaphomyia, discovered by Mr. Wallace 18 in 
New Guinea, is highly remarkable, as the males are 
furnished with horns, of which the females are quite 
destitute. The horns spring from beneath the eyes, and 
curiously resemble those of stags, being either branched 
or palmated. They equal in length the whole of the 
body in one of the species. They might be thought 
to serve for fighting, but as in one species they are 
of a beautiful pink colour, edged with black, with a 
pale central stripe, and as these insects have altogether 
a very elegant appearance, it is perhaps more pro- 
bable that the horns serve as ornaments. That the 
males of some Diptera fight together is certain ; for 
Prof. Westwood 19 has several times seen this with some 
species of Tipula or Harry-long-legs. Many observers 
believe that when gnats (Culickke) dance in the air in 
a body, alternately rising and falling, the males are 
courting the females. The mental faculties of the 
Diptera are probably fairly well developed, for their 
nervous system is more highly developed than in most 
other Orders of insects . 20 
Order, Hemijptera (Field-Bugs).— -Mr. J. W. Douglas, 
who has particularly attended to the British species, has 
kindly given me an account of their sexual differences. 
The males of some species are furnished with wings, 
whilst the females are wingless ; the sexes differ in the 
form of the body and elytra ; in the second joints of 
their antennae and in their tarsi ; but as the signification 
is c The Malay Archipelago,’ vol. ii. 1869, p. 313. 
19 1 Modern Classification of Insects,’ vol. ii. 1810, p. 526. 
20 See Mr. B. T. Lowne’s very interesting work, ‘ On the Anatomy of 
the Blow-Fly, Mnsca vomitoria,’ 1870, p. 14. 
