3036 



THE JOINTED ANIMALS 



FOREST FLIES Family HIPPOBOSCID^E 



This family brings us to the second section (Pupipara) of the Cyclorrohapha, 

 all the members of which are no less remarkable among flies for the strangeness of 

 their appearance than for their method of development. They are all short and 

 flat, with longish and powerful legs which enable them to run with great speed; 

 some of them being entirely wingless, with the mouth parts much reduced; but in 

 the mode of their development they are absolutely unique in the entire order. In 

 the first place only a single young one at a time is produced, and this, instead of 

 being laid in the egg stage, remains within the mother, nourished at her expense 

 by means analogous to those which obtain in the higher mammels. When born, 

 the young is either actually a pupa, or immediately assumes the pupa state, being 

 motionless, without segmentation, and entirely protected by a horny shell, which 

 imparts to it the appearance of the seed of a vetch. The members of this section, 

 which are mostly parasitic on birds or mammels, are referable to three families. Of 

 these, the forest flies are represented by several genera, all the members of which 

 are parasitic upon mammals or birds, and are frequently spoken of as ticks. The 

 species known from its abundance in the New Forest as the forest fly (Hippobosca 

 equina) has the wings well developed. It infests horses and oxen, usually attach- 

 ing itself to those parts of the body where the covering of hair is scanty. A second 

 kind, known as Ornithomyia avicularia, occurring, as its name indicates, on birds of 

 almost all kinds, also possesses a pair of fully -developed wings; but in another 

 species, Stenopteryx hirundinis, which is found on swallows and about their nests, 

 the wings are narrow and sickle-like and scarcely fitted for flight. A fourth 



species, the so-called deer tick (Lipoptena cervi), is pro- 

 vided with wings upon issuing from the pupa case; but 

 after flying about for a time the insects settle upon 

 deer, and drop their wings by fracturing them at the 

 base. The last member of the family to be mentioned, 

 the so-called sheep tick which must not be con- 

 founded with the mite of that name is entirely wing- 

 less from its birth. We thus get in this family a series 

 of forms starting with the fully-winged forest fly and 

 leading through the swallow tick with its wings reduced 

 in size, and the deer tick which can cast its wings, to 

 the sheep tick which has entirely lost these organs. 

 The second family of the group, Nycteribiidce, contains 

 the single genus Nycterbia, the species of which live 

 All are wingless and have lost their compound eyes, but 

 possess the balancers. The legs are long, powerful, and furnished with strong 

 hooked claws, by means of which they cling to the hosts they infest. The bee 

 louse {Braula cceca, G. on p. 3001), the type of the family Braulidce, is a minute, 

 blind, and wingless insect infesting honeybees; being found upon the workers, as 

 well as upon the drones and queen, but seeming to have a preference for the two 

 latter as hosts. 



COMMON FOREST FI,Y. 



(Enlarged.) 

 parasitically upon bats. 



