December, ’18] 
RUST: ANASTREPHA FRATERCULUS 
461 
and about 1 mm. in length. They are sometimes placed singly but 
often several occupy the same cavity and a single fruit may be ovi¬ 
posited in many times by the same or by different insects; thus it may 
happen that a fruit bears the marks of the ovipositors of so many 
females as to almost cover its surface with scars. 
The Larvae 
The eggs hatch, commonly in from two to four days, into minute 
white larvae, which immediately start eating their way through the 
fruit. These larvae are of the usual maggot type, slenderly pointed at 
the forward end and terminating bluntly at the opposite extreme. As 
they grow they also darken in color until when three-fourths grown 
they are creamy white, after which they become creamy, to yellow, 
and finally attain a length of from 7 to 9 mm. or even 10 mm. In 
summer the larval period averages from twelve to fifteen days, which 
may be prolonged to several weeks by the cold of winter. 
The Pup,e 
Upon becoming full grown the larvae leave the fruit and burrow 
several centimetres into the soil, there to form the pupa, which is of 
the usual castaneous, capsule-like type. Or the pupa may be formed 
under the first convenient object, or even in an exposed position if the 
larva cannot bury itself. The pupal period also varies greatly, ranging 
from twelve days to several weeks, according to temperature. 
The Adult 
Upon emerging from the pupa, the adult fly is very soft and can 
easily make its way through the small cracks and interstices of the soil 
until it reaches freedom at the surface. There its body hardens and 
the wings expand until it is able to fly in search of the fruit juices, sap 
or honey-dew upon which the adult normally feeds. 
In confinement the flies die within three or four days, unless supplied 
with food, but if syrup or juicy fruit is supplied them, they may live for 
astonishing lengths of time. Without any special attention, the 
writer has kept flies alive for more than three months and has no idea 
but that this period may be greatly prolonged under more favorable 
conditions. In this connection, it was noted that the males generally 
died first, just as they often are first in emerging from the pupa. 
Fertilization of the female often takes place during the first day after 
emergence, and eggs have been secured upon the third day, but gen¬ 
erally oviposition begins upon the seventh or eighth day after emer¬ 
gence and may continue for a long period. The maximum length of 
time during which a female may deposit eggs has not yet been deter- 
