INSECTS AND PLANTS 45 



So much for the history of the invasion of the cotton- 

 fields of the United States by the cotton-boll weevil. As for 

 the insect itself, there are more than thirty different species 

 of weevil to be found in the vicinity of the American cotton- 

 fields, so it is little ip be wondered at that cases of mistaken 

 identity occur, giving rise at times to local panics and a 

 massacre of the innocents ; for these other weevils do no 

 harm to the cotton, though some of them visit the cotton- 

 flowers in search of nectar. Our subject, however, is not 

 the only weevil that does damage to cotton, for another 

 species, Anthonomus vestitus, has recently been discovered 

 in Peru and Ecuador, where it is a serious cotton pest, 

 though, fortunately, it is at present unknown outside those 

 countries ; three other species, in addition, are also known 

 to do more or less serious damage to this useful plant. 



Very careful observations have been carried out by 

 American entomologists with a view to discovering the 

 food plants of the Mexican cotton-boll weevil, and, accord- 

 ing to their researches, the cotton plant is the original and 

 only food plant of this weevil. The importance of this dis- 

 covery may not be apparent at first glance, but, supposing 

 that the cotton-planters of a whole region should abandon 

 the cultivation of the plant, in order to escape the attentions 

 of the boll weevil, their efforts would be unavailing, if the 

 insect could subsist on some other plant or plants during 

 the period and then attack the cotton with renewed vigour 

 when its cultivation was resumed. If only on account of 

 the fact that the weevil appears to have but one food plant, 

 there is hope that crop rotation will materially decrease 

 the pest in time. 



The life-history of the cotton-boll weevil is not without 

 interest. The female weevil bores a cavity, either among 

 the immature anthers of a cotton square, or on the inner 

 side of one of the carpels of a boll or bud, and there de- 

 posits a pearly-white egg. The covering of each egg is 

 unmarked and soft but tough, thus allowing for consider- 



