470 DIPTERA CHAP. 



in habits, but the great majority are terrestrial, frequenting 

 trees, etc. The former larvae are very slender, and move after 

 the manner of leeches ; they give rise to iniagos with naked 

 wings, while the terrestrial larvae produce ilies with hairy 

 wings. There are also important distinctions in the pupae of 

 the two kinds ; the correlation between the habits, and the dis- 

 tinctions above referred to, is, however, far from being absolutely 

 constant.^ Certain species of midges are in this country amongst 

 the most annoying of Insects ; being of very minute size, scarcely 

 visible, they settle on the exposed parts of the body in great 

 numbers, and by sucking blood create an intolerable irritation. 

 Gcratopogon rrirms is one of the most persistent of these annoyers 

 in Scotland, where this form of pest is much worse than it is in 

 England ; in Cambridgeshire, according to Mr. G. H. Yerrall, 

 the two troublesome midges are the females of C. 2mlicccris and 

 C. hiiyunctatus. 



Fam. 6. Orphnephilidae. — Small, Iroiun or yelloxvish flies, 

 hare of inihcsccucc, until very large eyes contiguous in both sexes, 

 and with antennae eomposecl of two joints ctncl a termi^ial bristle ; 

 both the second joint and the bristle are, hoivever, really complex. 

 One of the smallest and least known of tire families of Diptera, 

 and said to be one of the most difficult to classify. The nervures 

 of the wings are very distinct. Nothing is known of the habits 

 and metamorphoses; there is only one genus — OrjJhnephila ; it 

 is widely distrilDuted ; we have one species in Britain. 



Fam. 7. Psychodidae (Moth-flies). — Extremely small, helpless 

 flics, usually with thichish antennae, bearing much hair, with 

 wings broader than is usual in small flies, and also densely clotJied 

 ivith hcdr, giving rise to a pattern more or less vague. These 

 flies are very fragile creatures, and are probably numerous in 

 species. In Britain forty or fifty species have been recognised.^ 

 A South European form is a blood-sucker, and has received the 

 appropriate name of Phlebotomus. The life-history of Pcricoma 

 canescens has. recently been studied by Professor Miall.^ The 

 larva is of aquatic habits, but is amphiljious, being capable of 

 existing in the air ; it has a pair of anterior spiracles, by means 



' For metamorphoses of aquatic species of Ccratopogon, see Miall and Meinert, 

 already quoted : for examjiles of the terrestrial species, and their illustrations, 

 refer to Mik, IFien. cnt. Zeit. vii. 1888, p. 183. 



*= Monograph, Eaton, Ent. Mag. xxix. and xxx. 1893, 1894 : supplement 02i. cit. 

 1896, etc. ^ Tr. ent. Soc. London, 1895, p. m. 



