59 



era lion. This phml I'aclor is i^cniTally responsible for 

 the destruclion ol" about 12 of 13 per cent, of all wee- 

 vil stages starting to develop and is therefore one of the 

 most important natural factors in weevil control. Pro- 

 liferation commonly extends beyond, and exceeds by 

 its own injurious effects, the direct injury which might 

 have been caused by the weevil stage which started it. 

 The abundance of this proliferous cell formation ap- 

 pears to vary with difl'erent varieties of cotton and also 

 in the same variety under different conditions of soil 

 moisture. 



Predacious Ants Helpful Insects. — About thirty other 

 insect species feed more or less upon some stage of the 

 boll weevil. The most important predatory enemy is 

 the little "fire ant" which occurs already distributed 

 through the cotton belt. These ants occur on most 

 types of soil but not everywhere in equal abundance. 

 Where they are numerous they may exert a very valu- 

 able control effect upon the boll weevil. These ants are 

 partly, at least, carnivorous and learn to cut their way 

 into the fallen infested squares especially and there 

 feed upon the helpless, tender grubs and pupae of the 

 boll weevil. Occasionally these ants have been found 

 to destroy more than half of the weevil stages in fallen, 

 infested squares but as a rule their control ranges be- 

 tween 12 and 20 per cent. The holes made by ants 

 entering squares resemble superficially the exit holes 

 made by weevils as they emerge but a close examina- 

 tion of the interior of the weevil cell shows that, where 

 ants have entered, the cell is left practically clean and 

 empty. On the other hand when the weevil has emerg- 

 ed there wall be left in the cell the remains of shed 

 skins from the weevil stage as it transformed, some 

 conspicious white particles of excrement voided by 

 the weevil before it ever fed and the fine material torn 

 away by the weevil as it formed the emergence hole 

 through the wall of its cell and the square. Many other 

 species of ants do a similar but less common good work 

 and a number of other insects feed occasionally upon 

 either adult or immature stages of the w^eevil. 



Parasites Are Not Dependable. — More than twenty- 

 five different species of insects and four species of 

 mites are known to attack the boll weevil as true para- 

 sites. These parasites have other native hosts and 

 simply include the boll weevil as it comes within their 

 range. Parasites attack more commonly the weevil 



