28o The Descent of Man. Part II. 



" backward and forward like two playful lambs. Then the 

 " female pretends to run away and the male runs after her with 

 " a queer appearance of anger, gets in front and stands facing 

 " her again ; then she turns coyly round, but he, quicker and 

 " more active, scuttles round too, and seems to whip her 

 " with his antennse ; then for a bit they -stand face to face, 

 " play with their antennae, and seem to be all in aU to one 

 " another." 



Order, Uiptera (Flics).— The sexes differ little in colour. The 

 greatest difference, known to Mr. P. Walker, is in the genus 

 Bibio, in which the males are blackish or quite black, and the 

 females obscure brownish-orange. The genus Elaphomyia, dis- 

 covered by Mr. Wallace " in New Giiinea, 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 a stag, being either branched or pal- 

 mated. In one of the species, they equal the whole body in 

 length. They might be thought to be adapted 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 probable 

 that they serve as ornaments. That the males of some Diptera 

 fight together is certain ; for Prof. Westwood '^ has several times 

 seen this with the Tipulae. The males of other Diptera ap- 

 parently try to win the females by their music : H. Miiller ™ 

 watched for some time two males of an Eristalis courting a 

 female; they hovered above her, and flew from side to side, 

 making a high humming noise at the same time. Gnats and 

 mosquitoes (Culicidssy also seem to attract each other by hum- 

 ming ; and Prof. Mayer has recently ascertained that the hairs 

 on the antennae of the male vibrate in unison with the notes of a 

 tuning-fork, within the range of the sounds emitted by the female. 

 The longer hairs vibrate sympathetically with the graver notes, 

 and the shorter hairs with the higher ones. Landois also asserts 

 that he has repeatedly drawn down a whole swarm of gnats by 

 uttaring a particular note. It may be added that the mental 

 faculties of the Diptera are probably higher than in most other in- 

 Bects, in accordance with their highly developed nervous system.^' 



" ' The Malay Archipelago,' vol. "' See Mr. B. T. Lowne's interest- 



u. 1869, p. 313. ing work, ' On the Anatomy of tlie 



" ' Moderi Classification of In- Blow-fly, Musca voraitoria,' 1870, p. 



lects,' vol. ii. 1840, p. 526. 14. He remarks (p. 33) that, " the 



*^ Anwendung, &c., * Verh. d, n. " captured flies utter a peculiar 



V. Jahrg.' xxix. p. 80. Mayer, 'n " plaintive note, and t'lat this sound 



American Naturalist,' 1874, p. -ioli. " causes other flies to disappear." 



