5 I 8 DIPTERA 



CHAP. 



them live by sucking blood from Mammals and Birds, and some- 

 times they are wingless parasites. The single member of the 

 family Braulidae lives on bees. The term Pupipara is erroneous, 

 and it would be better to revert to Eeaumur's prior appellation 

 Xymphipara. Mliggenburg has suggested that the division is 

 not a natural one, the points of resemblance that exist between 

 its members being probably the results of convergence. Eecent 

 discoveries as to the modes of bringing forth of Muscidae give 

 additional force to this suggestion. A satisfactory definition of 

 the group in its present extent seems impossible. 



Fam. 40. Hippoboscidae. Wings very variable, sometimes 

 present and large, then with waved surface and thick nervures 

 confined to the anterior and basal part ; sometimes mere strips, 

 sometimes entirely absent. Certain members of this family are well 

 known, the Forest-fly, or Horse-fly, and the Sheep-tick belonging to 

 it. The proboscis is of peculiar formation, and not like that of other 

 flies. Seen externally it consists of two elongate, closely adapted, 

 hard flaps ; these are capable of diverging laterally to allow an inner 

 tube to be exserted from the head. The details and morphology 

 of the structure have recently been discussed by Mtiggenburg. * 

 Mdopliagus ovinus, commonly called the Sheep-tick, is formed for 

 creeping about 011 the skin of the sheep beneath the wool, and 

 may consequently be procured with ease at the period of sheep- 

 shearing : it has no resemblance to a fly, and it is difficult to 

 persuade the uninitiated that it is such. Jfippobosca equina (called 

 in this country the Forest-fly, perhaps because it is better known 

 in the New Forest than elsewhere), looks like a fly, but will be 

 readily recognised by. the two little cavities on the head, one 

 close to each eye, in which the antennae are concealed, only the 

 fine bristle projecting. Very little seems to be known as to 

 the Natural History of this fly. Lipoptena cervi lives on the 

 Red deer ; the perfect Insect has apparently a long life, and both 

 sexes may be found in a wingless state on the deer all through 

 the winter. When first disclosed in the summer they are how- 

 ever provided with wings, but when they have found a suitable 

 host they bite off, or cast, the wings. The female, it appears, does 

 this more promptly than the male, so that it is difficult to get 

 winged individuals of the former sex. 2 Most of the known 



1 Arch. Naturgesch. Iviii. i.1892, pp. 287-322, pis. xv. xvi. 

 2 Stein, Deutsche ent. Zeit. xxi. 1877, p. 297. 



