286 Mr. Ernest Ewart Unwin on the 
last all the winter. In this latter case the larvee bury 
themselves in the soil, remain as pupe all through the 
winter, and reappear as flies in the early summer. The 
winter may be passed in the winged 
stage, the flies hibernating in some 
convenient place. 
It will be convenient to commence 
the detailed account with the larva. 
THE LARVA. 
The larva of Drosophila is a maggot, 
soft and white, about one-third of an 
inch long when full grown. There are 
apparently eleven segments behind the 
vestigial head, and between each seg- 
ment the body is roughened by a band 
of minute hooks. In general features 
it resembles the blow-fly larva (fig. 1). 
The anal processes are of two kinds: 
three pairs of small, conical, unjointed 
pseudopods arranged laterally, and a 
large dorsal retractile process, perhaps 
representing a united pair, which, pro- 
truding backwards and upwards, carries 
at its distal end the posterior spiracles 
(fig. 1). Professor Miall, in his account 
of the harlequin-fly,* refers to such 
appendages in the case of Nemoceran 
larvee. Like the prothoracic and anal 
feet of a Chironomus larva, these 
pseudopods of the Drosophila larva 
“may be the remnants of a series which 
once extended over many segments.” 
These pseudopods are covered with 
minute hooks. Their function is 
rather obscure. They may serve 
for locomotion by giving a better 
purchase to the body when moving 
through the food, and may also possibly enable the larva 
to keep its balance. The blow-fly larva has similar processes, 
which, according to my observation, are used in much the 
same way. 
Mouth-parts—The general structure of the mouth-parts 
* Miall (1900). 
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