83 
PUPATION IN OTHER SITUATIONS. 
While it is the normal habit of the bollworm to burrow beneath the 
soil to pupate, it will rareh^, either from necessity or otherwise, choose 
other situations. Coquillett (Ins. Life, I, p. 331) records four pupae 
of the late fall brood which were found by him in ears of corn at Los 
Angeles, Cal. Probably the warm winter climate of that region ma}^ 
be a factor in developing such an unusual habit. In several instances 
larvae confined in the laboratoiT with corn ears as food, but without 
earth, have pupated in a cavity eaten out of the ear. When this is 
done usually small bits of the surrounding tissues, or of paper, if 
such is present, are webbed together to form a sort of cocoon which 
more or less successfully conceals the pupa. In all our experience, 
however, not one was observed which had pupated in a cotton boll. 
This is probabl}^ on account of the rapid decomposition undergone by 
the injured bolls. In practice we obtained great numbers of pupae by 
confining large larvae under inverted tumblers supplied with sufficient 
food, but without soil. 
CHANGES UNDERGONE IN THE FORMATION OF THE PUPA. 
At the time it enters the soil the larva is somewhat stouter than it 
was just before, and the incisions between the body segments are 
beginning to become more distinct. (See PI. XII, fig. 2.) When it 
has formed its cell a period of quiescence ensues, which usually lasts 
for from two to four da^^s for the summer broods and much longer 
for the fall brood. During this time the larva decreases in length, 
gradually approximating the length of the pupa, and at the same time 
becoming stouter in the middle and more tapering distall}^, the inter- 
segmental constrictions growing more apparent. (PL XII, fig-. 3.) 
The coloring general^ becomes less brilliant and tends toward a 
greenish or yellowish tint with black markings. 
The larval skin splits medially along the dorsum of the thorax and 
the head of the pupa is passed through the opening, after which the 
skin is rapidly worked backward by the movements of the body, 
finally forming a loose mass at the base of the cremaster, where it is 
easily thrown ofi:' entireh\ This operation is all accomplished in the 
brief space of four or five minutes. The pupa is now very pale in 
color, usuall}^ with the head and thorax lemon-j^ellow. or often dis- 
tinctly greenish, especially on the thoracic dorsum and appendages, 
with the spiracles brown and the abdomen creamy 3^ellow. After an 
hour or two the abdomen has darkened considerably, the integument 
assuming a brown color and concealing the fat bodies beneath. From 
twelve to eighteen hours a^re required for it to gain the uniform 
brownish tint, which continues to darken for several da\^s longer. 
Pupae forming late in the fall do not undergo this final darkening until 
a short time before emergence the next spring. 
