48 



sap found in the pith sustained weevils for some time in the labora- 

 tory, but where obliged to puncture the stem, as they would be in the 

 field, they would never attack sorghum, except possibly freshly cut 

 stubble. Among the many plants tried, therefore, none has been 

 found to show any capacity for sustaining the lives of weevils in the 

 field in the absence of cotton. 



The question of the original food plant of the weevil has received 

 considerable attention from this Division, the investigations made in 

 Cuba being particularly thorough and conclusive. In that island some 

 varieties of cotton grow wild and are perennial. After most careful 

 search Mr. E. A. Schwarz wrote in the spring of 1903: "There is not 

 the slightest doubt, in my opinion, that the original and only food 

 plants of the weevil are the varieties of Gossypium and here in Cuba 

 the variety known as kidney cotton." The investigations of the 

 Division of Entomolog}^ have given special attention to the possibility 

 of the boll weevil breeding on other plants than cotton. Throughout 

 the investigations of Prof. C. H. T. Townsend in southern Texas and 

 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 carefuUj^ watched, and 

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

 practically certain that cotton is its only food. 



INSECTS OFTEN MISTAKEN FOR THE BOLL WEEVIL. 



Many species of insects have been mistaken for tlie Mexican cotton 

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

 have been an acorn weevil (PI. XIV, fig. 55) and a species commonly 

 found upon bloodweed or ragweed. The chief reason for the ijromi- 

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

 more closely 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 lioll 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 (PI. XIV, fig. 54) has been taken 

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

 was actually 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 (PI. XIV, fig. 58), is 

 much less cotiimon and therefore less frequently mistaken, but resem- 

 bles the boll weevil in general appearance far more closely than does 



