296 Mr. Ernest Ewart Unwin on the 
these are no doubt connected with copulation and serve as 
claspers (fig. 13). 
In the female we do not find a well-marked ovipositor. 
The parts which answer to an ovipositor are usually with- 
drawn into the 7th segment of the abdomen, but when 
protruded they are seen to consist of two valves between 
which the oviducal opening is situated. There are a 
number of small tubules situated in the 6th or 7th 
segments ventral to the oviduct into which they discharge. 
They may correspond in position to the collateral glands 
of the cockroach, but their function is not evident, as there 
is no cocoon secreted by Drosophila (fig. 14). 
When a male meets a female he follows her about the 
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Fie. 14. 
Fly (female) bisection of the terminal segments of the abdomen. (x 30.) c¢.g., so-called 
colleterial gland ; .¢., malphigian tubules ; 0, external opening of oviduct, od. ; 
r., rectum ; sp., spermatheca ; v., valve. 
surface of the food. The slight vibration of the wings and 
the short eager runs show how excited he is. He tries to 
get quite close to her, and now and then touches the tip 
of her abdomen with his proboscis. The male is repeatedly 
repulsed by a backward thrust of the female’s hind legs. 
To attract the attention of a female, the male will sometimes 
waltz rapidly round her two or three times, and then renew 
his attack at the rear. 
A fertilised female seeks out convenient spots for laying 
her eggs, preferring a part of the fruit that is not too 
moist. Although I tried the experiment repeatedly, I 
could not get a female to lay her eggs in a fluid. The 
method adopted was to imprison fertilised females under 
