8 REPORT 4, UNITED STATES ENTOMOLOGICAL COMMISSION. 
exposed part of tlie plant, even barking and girdling the stems. In 
feeding on the Lolls, however, it does not bore like the Boll Worm 
(Heliothis armigera), but eats the external parts as well as their con- 
tents. It is not knownjio thrive on any other plant than cotton, although, 
probability points to the belief that there will yet be found one or two 
more such food-plants, both at the North and at the South. 7 
As one correspondent naively puts it, " the worms feed only on cotton 
and one another," the cannibalistic propensity being freely indulged 
when the occasion presents. It is a common remark that tbe presence 
of the worm is easier detected by smell than by sight. The planter 
says that he can "smell the worm." There is a peculiar odor arising 
from the excrement, but particularly from the gnawed and. mutilated 
leaves, that gives rise to this saying; but where the worms are numer- 
ous and large enough to render it obvious, there they have already 
existed several days, perhaps weeks, in smaller numbers. 
When numerous enough to utterly defoliate a field before they have 
attained full growth, the worms will travel in all directions on the 
ground, and they have been exceptionally known to collect together 
and travel in vast bodies in their search for fresh food. 
THE CHRYSALIS. 
Having obtained full growth, the worm, in the language of the planter, 
" webs up," forming for protection a more or less perfect cocoon, usually 
within the fold or roll of a leaf sparsely lined with silken meshes. Here 
it contracts and thickens, the distinctive marks are nearly obliterated, 
and the green color acquires a verdigris hue. Withiu twenty-four hours, 
in midsummer, the skin splits just back of the head, and is gradually 
worked to the end of the forming chrysalis, now soft and green, but 
acquiring in the course of an hour or more a brown color and firmer con- 
sistence. This chrysalis state lasts, on an average, about a week in hot 
weather, but may extend to thrice that time with lower temperature. 
Where necessity obliges, the worm will 
spin up on any other plant or in any 
situation that offers shelter. In con- 
finement it will make a cocoon on the 
surface of the ground, covering and 
disguising the same with particles of 
earth, or it will even tra isform on the sliow cremaster from the side (a) aud. from be- 
ground without silk or shelter. Such malh *>; (After Kiley - ) 
cases rarely if ever occur in a state of nature, but when the worms are 
very numerous in a field the chrysalides frequently have their leafy pro- 
tectiOD eaten away, so that many of them either hang by the few hooks 
at the extremity, or fall to the ground. In no case, however, does the 
worm burrow in the ground as does the Boll Worm, or could the moth 
issue from the chrysalis were the latter accidentally buried even an inch 
beneath the surface. 
