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The larger bollworm larvae are preyed upon by several insects, 

 among the more important of which are several species of wasps 

 and ground beetles. The value of the common black and red wasps 

 which so frequently build nests in trees and outhouses near cotton 

 fields is imquestionable. At Paris, Tex., during 1905, a nest of the 

 former species, located in an old cotton house with several cotton 

 fields near by, was carefully observed for two hours. The nest con- 

 sisted of about 800 cells, with about 280 adults present at one time. 

 During the period of examination 168 wasps entered with food for 

 their larvae and for other adults. In 118 instances the food brought in 

 was recognized as being bollworm larvae. Probably the majority of 

 the other 50 wasps carried bollworms, but identification was impos- 

 sible, because the larvae were so badly mangled. 



Several large robber flies, so often seen in cotton fields, and a few 

 species of spiders, have been known to capture bollworm moths. 

 The common toad also is beneficial, for in several instances the 

 writers and others have found numerous bollworm larvae in its 

 stomach. 



There are published few records of bird* feeding upon bollworms, 

 yet there is every reason to believe that bollworm larvae and adults 

 are destroyed by many species. Domestic fowls are undoubtedly 

 valuable in reducing the number of bollworms on cotton located 

 near houses and barns. Several instances have come under ' the 

 writers' observation in which cotton adjacent to barns where chickens, 

 turkeys, and guineas were kept was practically free from bollworms, 

 while at some distance out in the fields the injury was quite severe. 



One of the most important checks upon bollworm increase is 

 the cannibalistic habit of the larvae themselves. After the larvae have 

 attained considerable size they are ever ready to engage in battle 

 with their fellows whenever they chance to meet. When two larvae 

 are of unequal size the smaller is usually killed and devoured by its 

 fellow, but if their size is about the same, both larvae often die as a 

 result of injuries inflicted upon each other. This factor is of greatest 

 importance in corn, for if all of the larvae hatching in the silks of an 

 ear should attain full growth nearly every ear would be completely de- 

 stroyed. The reduction in bollworm numbers in ears of corn, due 

 mainly to this cause, is illustrated by the following figures: During 

 August, 1905, 10 ears of corn were examined just after the silks 

 began dying, and 198 larvae in all stages of development were found. 

 This gives an average of 20 larvae per ear, most of which were small, 

 or about 10 times the number which would ultimately reach ma- 

 turity. Cannibalism is a less important factor among larvae on cot- 

 ton, as in that case the larvae are more generally distributed over the 

 plants and therefore meet less frequently. 



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