ARIZONA WILD COTTON WEEVIL. 9 



the hibernating weevils in their cells fall to the ground during the 

 months of the winter, spring, and early summer, and because of 

 their size and shape they are well adapted for being carried great dis- 

 tances out through the foothills on to the plains by the floods that 

 occur every season. Here they are deposited by the water, and, the 

 cells having been sufficiently moistened, the weevils emerge. Thence 

 they will fly in search of food, and if they have been carried out into 

 the zone of cotton the danger of infestation is quite apparent. It is 

 in this manner that the infestation is most likely to take place; 

 hence the importance of a study of the surface drainage carrying the 

 water from the infested mountains into the various rivers. 



In this connection the distribution of the plants through the 

 lower arroyos is especially important. In many localities these now 

 support weevils and so are a constant menace to cotton, while even 

 where the weevils are not now present they are always likely to serve 

 as stepping stones in the downward movement of the weevil main- 

 tained by the floods. 



In the course of the investigations several small plats of cotton 

 were planted, comprising in all a little over one-fourth of an acre. 

 On the 30th of July the writer noted several flared squares in this 

 cotton. Examination showed them to contain weevil punctures, 

 and a careful survey of the entire plat revealed the fact that a light 

 infestation of weevils was present. During the remainder of the sea- 

 son all infested squares and bolls noted were collected and a few 

 adult weevils were captured on the cotton. The infestation never 

 became heavy, but it was quite evident that some 10 or 15 weevils 

 arrived at the plat at different times during the next two months. 

 This is of course conclusive proof of the transfer from wild to culti- 

 vated cotton. 



Early in the season, when a survey of the countryside was made, it 

 was decided that the ranch where this cotton was planted was a 

 logical point for infestation by the boll weevil. It is located at the 

 junction of the arroyos from two large canyons, and consequently 

 receives a concentration of the water flow from these two canyons 

 and all intermediate territory. The Thurberia plant is quite common 

 throughout this drainage system and extends down to within a 

 fourth of a mile of the ranch, although the nearest plants found 

 infested with weevils are slightly farther away. The writer feels 

 that in the course of the weevil collections during the early summer 

 every weevil within at least a mile of the ranch was gathered; the 

 infestation must therefore have been due to weevils brought down by 

 the floods from some distance above. In fact the week before the 

 infestation was first noted there had been a number of rains in this 

 territory, and on one occasion the canyons had poured water down 

 into the washes and out as far as the ranch. These arroyos are nearly 



