BEX OF WEEVILS SURVIVING HIBERNATION. 



SEX OF WEEVILS SURVIVING HIBERNATION. 



ill 



We found it possible to readily and accurately recognize male and 

 female weevils without a partial dissection. In comparatively few 

 species of weevils are the males and females so closer) similar in gen- 

 eral external character as in the case of the Mexican cotton boll 

 weevil. Ii was found thai size depended primarily upon the loud 

 supply of the larva and that it had no special significance in regard 

 to sex, although it appears that (he averagemale is slightly smaller 

 than the average female. There exists a rather wide variation also 

 in coloration, which also proved to depend upon food supplj and 

 age rather than upon sex. 



SECONDARE SEXUAL CHARACTERS. 



We are indebted to Dr. A. D. Hopkins, of the Bureau of Ento- 

 mology, for indicating the most strongly marked points of difference 

 in the secondary sexual characters of the l>ol I weevil. The distinctive 



Mlf 



\ 





7/77V d length 38mm. ; tip to insertion /2mm. 

 y -~--x r /7s/ O >7 42 v ?) » » /8 " 



^^PPOPYG/D/UM- -^ ^ fg^/ ¥ 

 Fig. 9. Secondary sexual charai tersof Anthonomus grandis. | ui.t Hopkins.) 



characters (see fig. ( .)) are found upon the snout and upon the dorsal 

 side of the last two abdominal segments, which are normally almost 

 completely hidden by the wing covers. The differences are subject to 

 some variation but are still sufficiently constant to enable a close 

 observer to positively separate males from female-- with the aid of a 

 hand lens. Since these points of distinction Lave not previously 

 been published it seems advisable to include 1 them here, as they fur- 

 nish the basis for the determinations of sex which follow. 



Female. — The snout of the female is slightly longer and more 

 slender than that of the male. It usually tapers slightly from each 

 end toward the middle when viewed from above. The antennae 

 are inserted slightly farther Prom the tip than is tin 1 case in the male. 

 The insertion is at aboul two-fifths of the distance from the tip of 



the snout to the eye>. As a rule the surface of the snout is more 



smooth and shining than in the male. A slight depression, rather 



elongated and much larger than any of the other punctures upon the 



