VII 



BIBIONIDAE SIMULIIDAE 



477 



The 



vegetable. 



food of 

 The 



in the larval 



larva of 



changes 



state is 

 to a 



I g 



FlG - 2 - 6 - Portion of integument of Bibio sp. Cam- 

 bridge. , Intersegiueutal processes ; s. spiracle. 



be spiracles, 

 principally 



pupa inside the larval 

 skin ; the pupa is pro- 

 vided 011 the thorax with 

 two branched respiratory 

 processes that project 

 outside the larval skin. 1 

 Lucas has given an in- 

 teresting account of the 

 occurrence of the larva 

 of Bilno marci in enorm- 

 ous numbers at Paris ; 

 they lived together in 

 masses, there being ap- 

 parently some sort of 

 connection between the 

 individuals. 2 In the following year the fly was almost equally 

 abundant. 



Owing to the great numbers in which the species of Bibionidae 

 sometimes appear, these Insects have been supposed to be very 

 injurious. Careful inquiry has, however, generally exculpated 

 them as doers of any serious injury, though Dilophus febrilis a 

 so-called fever-fly appears to be really injurious in this country 

 when it multiplies excessively, by eating the roots of the hup- 

 plant. 



Fam. 11. Simuliidae (Sand-fries, P>uff<do-<jnats\ Small obese 

 jlii's 'tritli It n i/iju'd back, rather sJiurf Ay/ x and broad vo' ////*, tcilli short, 

 straight antennae destitute of sii/n ; prolnxris m>f p/'o/ir/i //;/. 

 There is only one genus, Sinudium, of this family, but it is very 

 widely spread, and will probably prove to be nearly cosmo- 

 politan. Some of the species are notorious from their blood-suck- 

 ing habits, and in certain seasons multiply to an enormous extent, 

 alight in thousands on cattle, and induce a disease that produces 

 death in a few hours ; it is thought as the result of an instilled 

 poison. S. columbaczense has occasioned great losses anuni^M, 

 the herds near the Danube; in Xorth America the Buffalo- and 

 Turkey-gnats attack a variety of mammals and birds. In Britain 



1 Pen-is, iii Ann. Sue. cut. France (2) v. 1847, p. 37, pi. i. 

 - Ann. Sue. nit. Frnnec :7>'i i. 1S71. Bull. p. Ixvii. 



