ox IXniAX PARASITIC FLIES. 
969 
There remain some further facts worth noting on the habits and 
structure of these dipterous parasites. Many species are destitute of 
eyes, and where ocelli are present, they are of such a simple kind that 
the insects’ power of vision must be of the poorest description. The 
anteimse are only two-jointed and are protected by deep pits at the 
base of which they are inserted. On the under side of the head there 
is a narrow groove into which fit proboscis and maxillary palpi. All 
these characteristics are features frequently found in many ecto- 
parasitic insects. With them may be also mentioned prehensile 
legs with clawed feet, ctenidia or combs, and the absence of wings. 
The pupiparous habit of the Nycteribiids was made known by 
J. 0. Westwood (1835) and some recent observations on this have 
been made by keeping fruit-bats in captivity and watchmg the doings 
of their parasites. When the time for her labour arrived, the female 
insect hurriedly left the bats and sought a suitable place to deposit her 
larva. Under natural conditions this would be some part of the tree 
where these bats congregate. The larva is a minute soft yellowish- 
white maggot of oval shape and dorso-ventrally compressed. It 
does not move and is covered with a sticky substance. Immed- 
ately after parturition the female stood over the larva and pressed it 
down with her thorax, causing it to adhere to the place where it was 
laid. She then hastened back to the bat. The males were never seen 
to leave the bats but they doubtless travel in search of females. In 
some species the female Nycteribiid fastens her larva to the host by 
means of the adhesive exudation. The place generally chosen is near 
the junction of the wing-membrane and the bat’s body. The larva a 
nnce assumes the shape of a puparium ; in half an hour it has hardened 
and darkened ; in 48 hours the transformation into a pupa is complete. 
The pupal stage lasts about a fortnight. For those species which 
deposit their larvae in the haunts of their hosts and not on their bodies 
this is a critical moment. The perfect insect must secure a host or it 
■will perish in about forty-eight hours. A newly emerged female Cy- 
clopodia has been observed to begin to breed in about ten days. Ten 
larvae were produced in twenty -nine days. For a fly this is not prolific 
and one may infer that mortality from failure to secure a host is not 
heavy. A lugh birth rate is not always a sign of prosperity nor of high 
evolution either in the vertebrate or the arthropod world. 
