1914} Melon Fly, Dacus cucurbitae. 193 
26. Number of generations annually.—In the Hawaiian 
Islands one brood of melon flies is followed by another through- 
out the year. Since the duration of the complete life cycle 
may vary from twenty-nine to forty three days, one would 
expect from eight to twelve generations a year. Assuming 
that a single female produces only ten descendants and that the 
sexes are produced in equal numbers at the end of the year she 
would be the ancestor of from 100,000,000 to 1,000,000,000,000 
offspring. 
VII. WEIGHTS OF THE EGGs, LARVAE, PUPARIA AND ADULT 
MELON FLIEs. 
Accurate weighings of the following stages in the life history 
of Dacus cucurbite were taken: eggs (plate XXXI, fig. 46) 
a few hours after these were deposited and again shortly before 
hatching; larve after hatching and every day thereafter (plate 
XXXI, figs., 47 and 52); recently, formed puparia (plate XX XI, 
fig. 53) and male and female melon flies. 
Pumpkins, in which melon flies had been induced to deposit 
their eggs, were taken from the field to the laboratory and three 
hours after oviposition, the eggs were removed and counted in 
two lots, each containing one hundred eggs. Each batch of eggs 
was placed upon a small piece of filter paper and weighed in a 
weighing bottle. The eggs were then transferred from the 
filter paper into a pumpkin and twenty four hours later, the 
same eggs were removed and weighed again. The weights of 
the eggs three hours and eyenty seven hours after deposition 
were as follows: 
TABLE III. 
WEIGHT IN MILLIGRAMS OF EGGS OF DACUS CUCURBIT#Z AFTER DEPOSITION, BEFORE 
HATCHING AND LOSS IN WEIGHT. 



3 hrs. after 27 hrs. after Loss in wt. 
deposition deposition in 24 hrs. 
Wt. of first 100 eggs.... 1.2 6. 1.2 
Wt. of second 100 eggs.. 7.5 6.1 1.4 
013 
Average wt. of l egg... .0735 .0605 
The result shows that each egg on an average, lost .013 
milligrams in weight, during the twenty-four hours between the 
two weighings. 
