656 
V 
DIPTERA. 
the life-history in the Sarcophagids and Tachinids has probably arisen 
for a rather different reason. Not only is it an advantage from the fact 
that the shorter the helpless period in the egg the less chance there is of 
destruction, but a short egg-period is of the utmost importance to such 
larvse as live in dead flesh and similar substances, owing to the rapidity 
with which the food on which they depend may entirely decompose or 
get completely dried up by the sun. Sarcophagids will often lay at 
least forty or fifty young larvae on one piece of meat, the main object 
evidently being to make certain that at any rate some of these shall get 
food at once and be able to make the best of their opportunity before the 
supply dries up or becomes otherwise unavailable. A number of articles 
on Hippoboscidce by Dr. Speiser in the last year or two of the ‘ ‘ Zeits- 
chrift fUr wissen-schaftliche Insektenbiologie ’ ? give a large amount of 
information about the family. He recognises five sub-families, of which 
four occurring in India are distinguished as follows :—the commonest 
Indian species ar e Hippobosca maculata, Lch., and its variety sivce, Big., 
on cattle, and H. capensis, Olf., on dogs (Hippoboscince) with Lynchia 
exornata, Sp., on pigeons ( Olfersiince ). 
Ocelli, and anal cell absent. Wings well developed. 
(1) Pronotum invisible from above . . .. Olfersiince. 
(2) Pronotum visible from above as a coloured 
projecting ring . . .. . . Hippoboscince . 
Ocelli present or absent. Wings either very weak 
or practically absent .. . . .. Lipoptenince. 
Ocelli present or absent. The wings developed or 
reduced, the former usually with an anal cell. 
Those with an anal cell possess ocelli; others have 
no distinct venation .. .. .. Ornithomyiince. 
NYCTERIBIIDiE. 
Wingless flies , with very small head bent back over the thorax when 
at rest. Legs long. General appearance spider-like. 
The Nycteribiidce are entirely parasitic, and are most remarkably 
modified in structure. They are found on bats, and cling to the skin or 
fur of their hosts. Their position is however the reverse of the usual one, 
since when thus clinging they have the back next to the body of the host 
and their ventral surface outward. To fit this attitude the head is bent 
