EFFICIENCY OF ADAPTIVE CHARACTERS OF ROLLS. fil 



pullod ;tiul Fxuiiiiued. Tlie first puncture was theu forty-two lioui-s old mid the 

 other four some twenty-four hours old. The examination revealed niarki'd pro- 

 liferation in every case, with no greater growth in that of forty-two liours' 

 duration than there was in that of twenty-four. Eggs had been laid inside the 

 wall of the boll, since it was easy, in the case of young, tender fruit, for the 

 weevil to cut an oiteuing to the lint. But every one of the five eggs had been 

 encysted by the proliferated tissue. It is quite possible that one or two of the 

 punctures reckoned as twenty-four hours old were still more recent. 



EFFICIENCY OF ADAPTIVE CHARACTERS OF BOLLS. 



The amount of protection att'orded in Guatemala by the weevil- 

 i-esi.sting characters of the bolls might be greatly underestimated if 

 it were to be supposed that the weevils make numerous attacks upon 

 the bolls for the purpose of feeding upon them. 



In their accounts of the habits of the l)oll weevil in Texas, Messrs, 

 Hunter and Hinds have devoted a chapter to '' eifects of feeding upon 

 squares and bolls,"" l)ut in Guatemala no indications were found that 

 weevils punctured the larger bolls for any other purpose than egg 

 laying. It is true that the outer surfaces of bolls are frequently 

 marked with scars of weevil punctures from which no larva? have 

 developed and no internal injuries have resulted, but these failures 

 can be explained in other ways than by the supposition that the wee- 

 vils feed upon the tough and innutritions outer walls of the bolls. 

 In Guatemala, at least, it appears that the weevil scars on large bolls 

 mark attempts at egg laying, though for a variety of reasons already 

 recited most of them are not elective. The only instance where wee- 

 vils were found feeding in bolls in Guatemala w^as at Rabinal. Two 

 weevils were together attacking a small boll, and had eaten out large 

 superficial pits, quite unlike the punctures in which eggs are laid. 



Feeding punctures in bolls are referred to by Mr. McLachlan in a 

 note dated at Victoria, Tex., August 31, 1905. Such injuries were 

 not found, however, to lead to the formation of external w^arts which 

 could be mistaken for egg punctures, doubtless for the reason which 

 Mr. McLachlan gives : 



It has been noticed that in bolls no proliferation occurs following the injury 

 from a feeding i)uncture, liowever serious that may i>e. Furthermore, from the 

 above and other observations it is apparent that ])roliferation is not excited by 

 the egg puncture or the egg, unless the puncture extends through the inside 

 tissue and the egg is tixed in the tissue or has been pushed through it to the 

 lint. In that ca.se a dense knob of proliferation ocoirs on the inner side of the 

 shuck, in tlie center of which the egg is often encysted. There nmst be a con- 

 stant irritant like the egg, with an opening to give it access to the lint, in order 

 to occasion the specialized growth. As a suggestiou it might be noted that all 

 the egg punctures are sealed by tlie adult weevil at the time -of egg laying, 

 while the feeding iiundnrcs arc left open. 



" Hunter. W. D.. and Hinds. W. E.. 1905. The Mexican Cotton Boll Weevil, 

 Bui. 51, Bureau of Entomology, V. S. Department of Agriculture, p. od, PI. VIII. 



