2 BULLETIN 1081, U. S. DEPARTMENT OF AGRICULTURE. 
DESCRIPTION AND LIFE HISTORY. 
EGG. 
The eggs (PL I, C, b) are of very unusual proportions, being long 
and slender, somewhat club-shaped or fusiform, with a long cylin- 
drical stalk. The average length is about 2.5 mm. and the greatest 
diameter is 0.2 mm. They are inserted into the seed cavity of the 
fruit from the long ovipositor of the female. The stalk sometimes 
remains partly in the flesh, although the eggs are never placed 
there as the young maggots seem unable to survive there. They 
always occur in clusters, and usually there is only one cluster to a 
fruit. The cluster consists of from 6 to 20 or more eggs, which are 
always fastened together by an adhesive substance on the surface 
of the eggs. One female, according to Knab and Yothers, is capable 
of laying 103 eggs, all of which are disposed of at about the same 
time. 
The eggs require from 12 to 14 days to hatch at any time through- 
out the year. Although the other stages are longer in winter than 
summer, the egg seems not to be affected by climatic changes. This 
point was determined by cutting open infested fruits at definite 
intervals after they were stung. ■ Usually an adult would oviposit in 
several fruits on a tree the same evening. It was then possible to 
cut one of these on each of several successive days until the eo-ors 
were found to have hatched. Even in the fruits which had been 
cut the eggs would complete their development if the halves were 
placed together, provided they were several days old when first 
exposed to the light and air. With freshly laid eggs this was not 
found to be true. Many attempts were made to rear the eggs arti- 
ficially after removing them from the fruit but without success. 
When dissected from the fruit and placed on a piece of leaf or 
fruit pulp over a plug of wet cotton in a vial inverted in water, 
as practiced by Back and Pemberton 3 with melon-fly eggs in Hawaii, 
they failed to develop. Even though the conditions of heat and 
moisture were apparently the same as in the fruit they did not 
hatch. 
When ready to hatch the eggs split longitudinally along the 
micropylar half and the maggot escapes, leaving the stalk end intact. 
LARVA. 
The young maggots on hatching from the eggs begin at once to 
feed on the coating of the seeds. They remain for about the first 
half of their existence within the seed cavity, feeding on the seed 
coverings and other fibers there. Manv of the seeds become de- 
3 Back, E. A., and Pemberton, C. E. The melon fly in Hawaii. U. S. Dept. Agr. Bui. 
491, p. 18. 1917. 
