192 Annals Entomological Society of America [Vol. VII, 
23. Do melon flies manifest fear?-—A melon fly is keenly 
aware of movements within its field of vision. When a large 
Odonata flies above a melon fly at rest on a cucurbit, the try- 
petid may tilt its head to follow the flying insect with its eyes. 
When one approaches a pumpkin slowly and carefully upon 
which a specimen is feeding, the fly may tilt its head and sway 
its body from side to side by bending the legs at the tibio- 
femoral joints. At such times a slight movement on the part 
of the observer will cause the fruit fly to take wing. The 
swaying movements of the alert insect may possibly be inter- 
preted as an external indication of fear. Howlett (7, pp. 415- 
416) believes that this swaying movement ‘‘seems to be asso- 
ciated with ‘courtship’ in all species of Dacus that occur at 
Pusa.’’ When the head of Dacus cucurbite is lowered, however, 
and the insect walks about with the wings held almost at right 
angles to the long axis of the body one can then approach the 
pest without danger of causing flight. 
24. Number of days required before the adults begin to oviposit. 
—An attempt was made to determine the number of days re- 
quired before the egg-laying period begins, after the melon 
flies issued from the puparia. A large number of adults upon 
emerging, were kept in breeding jars and fed on diluted molas- 
ses, fruit and vegetable juices and on water. After having 
been kept in captivity for eight days, three females were dis- 
sected but no fully-developed eggs were found in the ovaries. 
A daily dissection of three fruit flies was continued from now 
on, and at the end of fourteen days twenty-three ripe eggs were 
counted in the two ovaries of one fly, but others did not show 
mature eggs in the ovaries at the end of sixteen days. At the 
end of seventeen days, thirty-one eggs were dissected from the 
ovaries of another specimen. In all probability, the effect of 
confining the insects in breeding jars plays an important part 
in the rate of development of the eggs. 
25. Summary of stages of the life history—The duration of 
the different stages of the life history of Dacus cucurbita may 
be summarized as follows: 
DAYS 
Bieormertodis tasiyewaeor sce tere ae 1y4— 1% 
Ikanvallpertodiag.cen cecunt sy err 3%4—l11 
Pupaliperiod. cre. et errr ee 10 —14 
Beodayine begins... seas. ae 14 —17 after the adults emerge. 
29 —4314 
