12 BULLETIN 918, U. S. DEPARTMENT OF AGRICULTURE. 



of the moth. From an examination in 1919 of over 16,000 green 

 bolls that averaged over 2.5 larvae per boll, not a single pupa or pupal 

 skin was found. Should a larva cut a hole in a green growing boll 

 for the issuance of the moth, this hole would probably close from 

 proliferation before the pupal stage of 9.3 days is passed. 



Occasionally, in mature or dry bolls, as distinguished from green 

 ones, more than a mere exit hole is cut when the larva reaches the 

 carpel wall. The carpel tissues and the adjoining lint are cut away 

 and an elongate pocketlike cavity is made large enough for the larva 

 to become straightened out in its final preparation for pupation. 

 When this is done a light cocoon is spun inside this cavity and a hole 

 cut through the carpel wall to the outside. The last remaining parts 

 of the carpel wall are not cut entirely out leaving an open hole, but 

 the particles are held together and in place by a few fine strands of 

 silk which are easily broken and pushed away when the moth emerges. 



The very fact that only a few larvae pupate in the bolls is con- 

 clusive enough that there are other more favorable places for pupa- 

 tion. These places are either on the ground or in the ground. If the 

 moisture conditions are sufficient on the surface, they may spin a 

 cocoon in the trash or on any convenient object, and pupate there; 

 but if it is too dry and the soil is loose they may burrow as deep as 3 

 inches below the surface, make an earthern cell, line it with a very 

 fine, tough cocoon, and pupate there. During the summer a good 

 many pupa? are probably destroyed by cultivation, but when pupa- 

 tion takes place in the ground, only the exit passage being destroyed 

 and the pupa itself not molested, the moth may be able to escape 

 because of its burrowing power. 



Fullaway (3) and Busck (8) found that in Hawaii pupation nor- 

 mally takes place in the boll and only rarely in the soil or other 

 places. Maxwell-Lefroy (B) found that in India pupation occurs in 

 the boll or on the bracts or leaves of the cotton, and in unirrigated 

 black cotton soil might be found in a crack of the dry soil. Will- 

 cocks (7, p. 113) says that in Egypt — 



Pupation seems most often to take place on the ground under the fallen leaves, or 

 in the fold of a dead leaf or again between two dead leaves, also on old bolls which have 

 dropped or been broken off, and under or attached to small lumps of earth. In fact 

 they may be looked for amongst any shelter of this kind. One' situation was noted 

 that seems to be especially favored by the larvse as a haven to pass the pupal stage, 

 this was furnished by the dead flowers which are of course very numerous below the 

 plants. 



In Mexico pupa? were never found on the leaves or bracts under 

 field conditions. When green bolls were picked and left in sacks the 

 emerging larva? would sometimes hollow out a slight depression and 

 pupate near the base of the boll, or they would pupate between the 

 involucre and boll without making a depression, or spin their cocoons 



