THE BIBIONID.-E. 153 



The members of this family fretiuent meadows, and appear in great 

 numbers, such as Bihio. They mostly appear in the spring, but some 

 are autumnal insects, and they may even appear in midwinter 

 {DUophus). This latter genus also occurs in great abundance in hop 

 fields, where the "fever fly," as it is called, does great damage. 

 Haliday also says they appear plentifully on sand-hills. The genus 

 Scatopse may be found in outhouses, on walls and windows, while 

 some frequent flowers {S. notata), and others are abundant on trees, 

 feeding on the honeydew of the Aphis {S. picea). Many appear in 

 swarms or clusters. " In 1862 it {D. febrilis) was recorded as hang- 

 ing in millions on flowers, and in bunches on grasses."* It is not 

 uncommon to find clusters of them under the bark of trees. In 1887 

 I noticed this character in particular in a Scatopse at Hastings. It 

 appears to be the females that have this gregarious habit ; the males 

 may usually be found hovering about in the air ; their flight is slow 

 and heavy. Some of this family are double-brooded, such as the 

 common fever-fly, which appears in spring and autumn, i:)ut the 

 majority seem to have only one brood. Although it is a small 

 family, and evidently on the decline, the number of specimens is very 

 great. They are very abundant all over England, as many as forty- 

 two species being recorded, nearly all of which are fairly common 

 and some appearing in immense numbers. 



The lame of this family are cylindrical or fusciform maggots, 

 living in the earth, in dung, stems of plants, and at the roots (^Dilo- 

 plius) destroying the vegetation ; the grass roots and corn are 

 especially attacked and destroyed {Bilno and Dilophus), others 

 {Scatopse) feed on decaying animal and vegetable substances. The 

 maggots occasionally do great damage, as in the case of the lever-fly 

 {Dilophus febrilis), to be described later. The larvae are furnished 

 with twenty spiracles and with transverse rows of hairs ; generally 

 whitish-brown in colour, with brown head, which is armed with two 

 biting mandibles {Bibio). 



The lar-c^a of B. pomonce (Fig. i, Plate iii.). This maggot when 

 full-grown is about three-fourths of an inch to an inch long, of a chest- 

 nut brown colour and somewhat flattened dorso-ventrally. The head 

 is much smaller than the body segments and densely chitinous, orna- 

 mented with three pairs of large bristly hairs and several smaller ones. 

 Tile body is divided into twelve segments, the first being narrow and 

 having two rows of fleshy tubercles ; the remaining segments are 

 large, and each one with a single row of six tubercles, the twelfth 



* Man. Inj. Insects, p. 129. — Ormerod. 



