8 REPORT 4, UNITED STATES ENTOMOLOGICAL COMMISSION. 



exposed part of the plant, even barkiDg and girdling the stems. In 

 feeding on the bolls, however, it does not bore like the Boll Worm 

 (Eeliothis armigera), but eats the external parts as well as their con- 

 tents. It is not known to thrive on any other i)lant than cotton, although 

 probability i)oints to the belief that there will yet be found one or two 

 more such food-plants, both at the IsTorth and at the South."'' 



As one correspondent naively puts it, " the worms feed only on cotton 

 and one another," the cannibalistic propensity being freely indulged 

 when the occasion i^resents. It is a common remark that the 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. 



Wlien 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 i>rotection 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 nearl^^ obliterated, 

 and the green color acquires a verdigris hue. Within 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 



,, ., .,, J _o ^1 Fig. 4.— Chrysalis OF Alexia: enlarged to 



earth, or it will even trailStorm on the show ciemaster from the side (a) and from be- 



ground without silk or shelter. Such "^'^^^ ''^- ^^'''' ''''''■^ 

 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 i^ro- 

 tection 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. 



