38 THE MEXICAN COTTON-BOLL WEEVIL. 



SEASONAL HISTORY. 



THE ADULT WEEVIL. 



EMERGENCE. 1 



(PL IV, b, e; PI. Xl,e,f.) 



The adult boll weevil's normal method of escape from squares and 

 small bolls is by cutting with its mandibles a hole just the size of 

 its body. In large bolls the escape of the weevil is greatly facilitated 

 by the natural opening of the boll. Often the pupal cell is broken 

 open by the spreading of the carpels, and when tins is the case the 

 pupa, if it has not already transformed, becomes exposed to the attack 

 of enemies or, what is probably a more serious menace, to the danger 

 of drying so as seriously to interfere with a successful transformation. 

 If the cell remains unbroken the weevil always escapes by the path 

 of least resistance, cutting its way through as in the case of a square. 



CHANGES AFTER EMERGENCE. 2 



At the time of emergence the weevils are comparatively soft, and 

 they do not attain their final degree of hardness for some time after 

 they have begun to feed. The chitin is of an orange tinge at the time 

 the weevils leave the squares or bolls, but after exposure for some 

 time it turns to a dark chocolate brown. 



PROTECTIVE HABITS. 



Not only is the boll weevil protected from its enemies by its color, 

 which resembles both the dry squares and also the pulverized soil 

 upon which it frequently drops, but it has a protective habit, found 

 more or less commonly among insects. At the first disturbance of 

 the cotton plant, or sometimes even at a movement of a large object 

 in the vicinity of the cotton plant, the boll weevil becomes very alert, 

 raising its antennae and standing almost motionless. If the disturb- 

 ance continues, the weevil falls to the ground with its legs drawn up 

 close to the body and the antenna? retracted against the beak, which 

 is brought inward toward the legs. In this position it often remains 

 motionless for some time, but if further disturbed, it will start up 

 quickly, run a short distance and again fall over, feigning death. 

 This habit is popularly known as "suiting" 3 or "playing possum." 

 Frequently, in falling, the weevil comes in contact with some part 

 of the plant and immediately relaxes and takes shelter on the plant, 

 or sometimes it spreads its wings and flies away instead of falling 

 to the ground. In July and August the weevils become more alert 

 than at any other season of the year, and flight more frequently 

 follows the dropping from the plants. 



FOOD HABITS. 



Before escaping from the square the adult empties its alimentary 

 canal of the white material remaining therein after the transformation. 

 The material removed in making an exit from the cell is not used as 



1 E stracted from Bull. . r >l , Bureau of Entomology, pp. 39, 40. 

 s Extracted from Bull. 51, Bureau of Entomology, p. 40. 

 8 Undoubtedly a corruption of "sulking." 



