68 



HABITS OF NEWLY HATCHED LARY^ ON COTTON. 



The feeding habits of the newly hatched larvse have a very impor- 

 tant bearing on the question of poisoning and have for this reason been 

 rather carefully studied. The habit of eating the deserted eggshell 

 has already been described. After this follows a period of very pre- 

 carious existence for the young larvae. They begin to wander about 

 in search of suitable food, here and there rasping the epidermis of the 

 leaf or involucre where they happen to be, and passing on to repeat 

 the process. They are not satisfied to remain on the leaves, and very 

 often reach some tender growing tip soon after hatching. This is 

 usually to their liking, and the}^ remain and feed for some time upon 

 the tender foliage. They do not stay long, however, and are soon 

 again on the move after a short interval. If a square is next .found 

 they at once crawl beneath the involucre and begin feeding. Other- 

 wise they may feed to a slight extent on a leaf, or another growing 

 tip, until a square is finalty found. 



During the search for proper food many of the larvae perish; in fact 

 the great majority of them do. A number of times during the summer 

 from 100 to 150 eggs or newly hatched larvae placed on a cotton plant 

 have yielded only four or five larvae after a few daj^s. This is much 

 in excess of the number of eggs usually laid on a plant, and serves to 

 show what an enormous number of the larvae die in the presence of 

 food in plenty. 



One thing which is important and should be borne in mind is that 

 the larvae almost alwa3^s feed to some extent on large leaves or tender 

 foliage before they begin feeding inside the squares. If they are to 

 be poisoned it must be largely during this period of external feeding. 



EFFECT OF EXTERNAL CONDITIONS ON NEWLY HATCHED LARVAE. 



The j'^oung larvae feeding on corn early in the spring are often 

 washed down by rain and submerged for considerable periods. To 

 test their ability to withstand such conditions a number were experi- 

 mented upon in the laboratory. Twenty newly hatched larv^ were 

 entangled in a bit of cotton and submerged for seventeen hours. All 

 but four survived the immersion. Larger larvae can not stand such 

 long periods, but when dropped into water make feeble attempts to. 

 escape, becoming stupefied after a few minutes. 



CHARACTER OF INJURY. 



The characteristic habits of the larger bollworms, like those of the 

 newly hatched larvae, are utterly difierent on corn and cotton and must 

 be considered separately. 



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