BIOLOGY OF ARIZONA WILD COTTON WEEVIL. 



23 



On January 2, 1915, all bolls were collected from the cages and 

 examined for weevil injury or stages. The results are shown in 

 Table VIII. 



Table VIII. — Weevil stages found in cotton bolls taken from caged plants, Jan. 2, 1915. 





Bolls. 



Live weevil stages. 



Dead weevil stages. 



Cage No. 



Not 

 injured. 



Injured 

 but no 

 weevil 

 stages 



present. 



Larvae. 



Pupae. 



Adults. 



Larvae. 



Pupae. 



Adults. 



9 In 



1 



8 

 16 



7 

 2 















8 



7 















3 .... 



11 

 5 

 6 





2 

 1 

 1 



3 

 4 

 6 









6 



2 

 1 





1 

 1 





7 











Total 



44 



34 



3 



4 



13 





2 









The fact that only two weevils had emerged/ both from fallen bolls, 

 indicated the strong adherence of the weevil to the cell hibernation 

 habit, even when transferred to cotton. One of the weevils which 

 had emerged was found active on the ground and, judging from its 

 condition, it had emerged only a short time before collection. A 

 comparison of the number of immature stages found in these cotton 

 bolls with that found in Thurberia bolls in a similar cage test shows 

 the retarded development under the unnatural conditions of a cotton 

 boll. 



PARASITES AND PREDATORY ENEMIES OF THE WEEVIL. 



In the course of the season's investigations several hundred infested 

 Thurberia bolls were collected at various points in the Santa Catalina 

 and Santa Rita Mountains and the. adult weevils were reared. In 

 spite of the great number of these bolls which were utilized, not a 

 single parasite emerged. Not a record of weevil parasitism was 

 made by the writer during the entire season. 



Only one case of predaceous insects attacking thurheriae was noted. 

 On September 25 in the arroyo below Saw Mill Canyon, Santa Rita 

 Mountains, at about 3,500 feet altitude, three Phymatidse were 

 observed feeding on adult weevils. These have been determined by 

 Mr. Otto Heidemann as Phymata erosa veir.fasciata Gray (one female) 

 and Macro cepJialus inequalis Champ, (two males). The latter of 

 these was the more abundant at this time. 



WASHINGTON : GOVERNMENT PRINTING OFFICE : 1916 



