4 BULLETIN 231, U. S. DEPARTMENT OF AGRICULTURE. 



immediately on both foods, but usually fed slightly more on the cot- 

 ton squares than on the Thurberia buds. When egg deposition 

 started the greater number of the eggs were deposited in cotton 

 squares. These observations were continued for 15 days. 



From these experiments it would appear that, when in captivity, 

 weevils reared from Thurberia will feed on cotton squares just as 

 readily as they will on Thurberia buds. The slightly greater amount 

 of feeding on cotton squares in this experiment may or may not 

 have any significance, and it was probably purely accidental. 



These records made in the laboratory are in strong contrast with 

 those made in the field. At Victoria the Thurberia plants under 

 cultivation were within 50 feet of a small patch of cotton. This 

 cotton was heavily infested by weevils throughout the season and 

 not a boll was able to reach maturity. On the other hand, although 

 the Thurberia plants were just as much exposed as the cotton, not a 

 single indication of weevil work was found on the plants and not a 

 weevil was found on them. 



In Stone Cabin Canyon, Santa Kita Mountains, Ariz., Mr. W. D. 

 Pierce was unable to find a weevil on cotton plants growing within 

 10 feet of Thurberia plants which were heavily infested with weevils. 

 In December this same cotton was examined by Messrs. Schwarz 

 and Barber and they were unable to find a sign of weevil work in the 

 bolls. 1 



In this connection records made on the habits of larva? of the cotton 

 leaf worm (Alabama argillacea Hubn.) are of interest. These larvae are 

 almost exclusively cotton feeders, but in the laboratory tests they 

 fed on the Thurberia leaves as readily as on cotton when both were 

 offered and were able to pupate and reach maturity on this food. 

 In Stone Cabin Canyon this species was found feeding on Thurberia 

 plants. The species was common on cotton at Tucson and Phoenix, 

 Ariz. At Victoria, Tex., this species acted exactly as did the native 

 weevils, with relation to the cotton and Thurberia patches. The 

 cotton was heavily infested and only preserved from destruction by 

 spraying, but not a single leafworm larva was ever found on the 

 Thurberia plants. The moths were very numerous for a considerable 

 period and eggs were abundant on the cotton, whereas careful 

 examination failed to show an egg on the Thurberia plants. 



CHARACTERISTICS OF THE ADULT. 



DESCRIPTION OF THE SPECIES. 



Owing to the recent studies on the variations of this species it 

 becomes necessary to reconstruct the descriptions given by Boheman 



i Experiments during 1914 in Arizona have proven that the Thurberia weevils will attack growing 

 cotton. 



