960 JOURNAL, BOMBAY NATURAL HIST. SOCIETY, Vol. ZXVlIi. 
the nests and there pupate. The larva does not feed and only one is 
produced at a birth ; but as the Hippoboscids have spread over the 
globe, and in some countries are relatively abundant, one must assume 
that the slow birth-rate 'is compensated for by the avoidance of mani- 
fold dangers which assail larval life. 
]\Iost Hippoboscids have no distinct neck and the head is sunk 
deep in the thorax, so as to be protected when working a way over 
the host’s body. The wings of Hippoboscids are an interesting subject 
of study. In comiection with the sedentary life, which parasitism 
tends to produce, there is a progressive reduction of the wings until 
in the genus whichisa sheep parasite, wings are always 
entirely absent. These are wingless flies incapable of flight which 
pass the whole of their existence on their hosts and which can only 
get to a new host when the two sheep are touching or in close proximity. 
In the sub-family Hippoboscince the wings are well developed. In the 
Lipoptenince the wings are very weak and often practically useless. 
In some species, which are parasites of deer, male and female flies 
emerge from the pupal stage with wings which they use to reach a 
host. Those of the female at once break off leaving a pair of stumps ; 
or it may be that she rids herself of organs which are of no more use. 
Once in the coat of the deer she has conquered the problem of nour- 
ishment. The problem of reproduction involves a visit from a male 
fly. The males appear to retain their wings longer, possibly until 
they have found a deer with female parasites. Later in the season 
both sexes cohabit in a wingless condition as parasites in the hairs 
of the host. Lipoptena moschi is a parasite of the musk-deer. L. 
gracilis has been obtained in India from chevrotams. L. pteropi 
occurs in Ceylon on fruit eating bats. 
In the Oljersiince the wings are well developed whilst in the Orni- 
thomyiince they are often fairly substantial. In some cases they are 
reduced to mere rags or shreds. Now both these sub-families are 
typically bird parasites. Lynchia exornata Sp. , which occurs frequently 
on pigeons in India, is a member of the first named group. It would 
seem that the wings are retained by the bird parasites as a useful 
adjunct in connection with winged hosts. When a bird infested by 
these flies is shot, one or more flies will often follow the sportsman 
who carries the dead host, sometimes alighting on him and seeking 
refuge in his hair, beard or clothing. 
But even in the winged Hippoboscids there are signs of incipient 
atrophy of the wings which must be attributed to the effects of para- 
sitic habits. The veins are crowded together along the anterior 
wing-border, whilst the few veins which run obliquely across the wing 
are lacking in strength. 
Some account of the life-history and structure of Hippobosca 
maculata, a well-known Indian cattle fly, will serve to illustrate the 
