83 



of the adult, varied between nine and sixteen days, in most cases being 

 about twelve or fourteen days. The time required for the emergence 

 of males seemed to average about one da} T shorter than that for females. 



ADULT. 



The moths of this species measure from 1 to li inches in length with 

 the wings closed. The predominant color as seen from above is white 

 with prominent black spots scattered over both the upper and under 

 surfaces of the wings and in six rows, three ventral, two lateral, and 

 one dorsal, along the abdomen. In the female the wings are white 

 upon the under as well as the upper sides. The back of the abdomen, 

 with the exception of the first and last segments, is of a brownish 

 yellow color. In the males the under surface of the forewings, both 

 surfaces of the hindwings, and the predominant color of the abdomen 

 is brownish yellow, thus making the distinction of the sexes a A r ery 

 easy matter. 



GENERATIONS. 



The average time required for the development of this generation 

 was very nearly forty -live days. The adults, all of which emerged, 

 mated within a few days and the females deposited their eggs in the 

 breeding cages. No attempt was made to breed another generation, 

 but as numerous large larva? of this species were seen early the follow- 

 ing spring, it appears that a fall brood of larva? is normally developed 

 and that this brood hibernates in the larval stage. No adults were 

 seen early in the spring of 1903. Hibernated caterpillars taken into 

 the laboratorj^ spun up about the middle of May. 



In 1902, the eggs for the generation of worms which did so much 

 damage during the latter part of July must certainly have been 

 deposited by the last of June, and it is very probable, though the actual 

 fact has not been established, that the adults depositing those eggs 

 had come from hibernated caterpillars. Assuming that to have been 

 the case, the normal number of generations for this insect in that 

 locality is three. The period during which the life histor}- was fol- 

 lowed in 1902 was exceptionally hot, and it is therefore safe to say that 

 the normal developmental period for each summer generation is about 

 seven weeks. 



It is believed that in the Middle States this species has two gen- 

 erations and in the New England States it has been found to have but 

 one. 



INJURY TO COTTON. 



The occurrence of this caterpillar upon cotton is by no means rare. 

 In fact, occasional specimens may be found in almost every cotton 

 field, but it is onlv very rarely that thev are as abundant and inflict 



