66 



in Mexico and the careful studies made by Mr. Schwarz in Texas and 

 in Cuba and the observations made by the writers in Texas every 

 plant closely related to cotton has been most carefully watched, and 

 the uniform failure to find the weevil upon any other plant makes it 

 practicallj^ certain that cotton is its only food. 



INSECTS OFTEN MISTAKEN FOR THE BOLL WEEVIL. 



Many species of insects have been mistaken for the Mexican cotton 

 boll weevil. Among them the two most commonly reported in Texas 

 have been an acorn weevil (PI. X, %. 43) and a species commonly 

 found upon blood weed or ragweed. The chief reason for the promi- 

 nence of these two species is not that they resemble the boll weevil 

 more closel}^ than do others, but rather that their habits bring them 

 into closer proximity with cotton fields and their abundance has led to 

 their more frequent discovery. The acorn weevil has in a number of 

 cases been taken in lantern traps set in cotton fields, and the mistake 

 in the proper identification of the species has given currency to the 

 report that the boll weevils are attracted to lights, which, however, is 

 never the case. There is no authentic record of a single boll weevil 

 having been caught at any light. Only very rarely and under excep- 

 tional conditions will the acorn weevil feed at all upon cotton bolls. 



Though the bloodweed weevil (Plf X, fig. 42) has been taken from 

 cotton plants, no evidence has been submitted showing that it was 

 actuall}^ feeding thereon,, and it is more likely that such specimens had 

 merely strayed to the cotton from bloodweed growing near. 



Another species of weevil, Desmoris scapalis (PL X, fig. 46), is much 

 less common and therefore less frequently mistaken, but resembles the 

 boll weevil in general appearance far more closely than does either of 

 the species previously mentioned. This insect has been found attack- 

 ing white prickly poppy {Argemone alba) and tumbleweed {Arnaraiithus 

 grd&cizans) in the spring, and probably breeds on Prionopsis ciliata 

 Nutt. and the broad-leaved gum plant {Grindelia squarrosa). 



In general the food habits of any species are among its distinctive, 

 specific characters, and as the structural differences are easily over- 

 looked and difficult of appreciation by anyone unacquainted with the 

 careful study of insects, a rather full though by no means complete 

 list is here given of the species which have been reported to the Bureau 

 of Entomology as having been confused with the boll weevil. A num- 

 ber of the most common species will be found figured among the illustra- 

 tions in Plates X, XI, and XII. The scientific names of the insects are 

 given because they are definite and refer positively to a single species, 

 whereas the common names are used so loosely that the same name may 

 be applied to a number of species having possibly similar habits. In 

 many cases no common name has 3^et been given to the species. Eight 

 of the species mentioned attack living cotton and five species are found 

 feeding only on decaying bolls. The occurrence of the remainder upon 



