703 
ON INDIAN PARASITIC FLIES. 
BY 
Hakold Russell, f.l.s., f.z.s. 
II 
With Tiro Plates 
{Continued from page 380 of this Volume.) 
III. 
The Muscoihea. 
The next five families that must be mentioned in connection with 
parasitism and Diptera {Taclnnidce, Dexiidee, Muscidee, Sarco- 
'phrtgidcB and (Eslridce) all belong to the super-family Muscoidea of 
Townsend. It is very noteworthy that this Muscoidean stock has 
developed three separate and absolutely distinct types of parasitism, 
or at least feeding, on mammals. * All three have the same aim, 
which is to nourish the dipterous larvae at the expense of the Mam- 
malia. What is interesting is that each of the three has attained 
the same result in such fundamentally opposite ways. 
1. In the first group come Cuter ehra {(Eslridce) and its allies. 
The end is attained by subcutaneous or internal larval endoparasitism. 
The larva does all the feeding and the imago takes no nourishment 
whatever. To such a complete extent does this prevail that the 
adult mouthparts are atrophied and do not function at all. The 
Oestrid habit of parasitism seems to be the oldest of the three. 
2. In the second division we have Glossina {Muscidee) the genus 
which includes the tse-tse flies. The same result is attained by 
supracutaneous imaginal blood-sucking which strictly speaking is 
not ectoparasitism. This is the exact antithesis of the preceding. 
The adult fly does all the feeding by blood-sucking. But it retains 
and nourishes the larva within the oviduct until full grown. The 
larva is then extruded and almost immediately becomes a pupa 
without feeding any more. 
3. In the third division we have the case of the Congo floor-maggot 
{Auchmeromyia), another of the Muscidae. The fly produces a 
blood-sucking larva. The desired result is here obtained by sup- 
racutaneous larval ectoparasitism. It is a remarkable method be- 
cause unique among dipterous larvae. The larva sucks blood ex- 
* C. H. T. Town.send. “The Taxonotn}' of the Muscoidean flies 1908) Snnithso- 
®ian Miscellaneous Collections. Vol. 51. 
17 
