10 PROCEEDINGS ENTOMOLOGICAL SOCIETY 



absolutely no signs of the plant. Outside of our records Thur- 

 beria is known also to occur in the Mule Pass, Chiricahua, and 

 Huachuca Mountains, at Ft. Bowie, Davidson Springs and near 

 Dragoon, Arizona, and in southwestern Chihuahua and Guadala- 

 jara, Mexico. 



In altitude the plant occurs from 2300 (Fish Creek Canyon, 

 Arizona) to 5000 feet. (Sawmill Canyon, Santa Rita Mountains, 

 Arizona.) According to Mr. F. L. Lewton it occurs as high as 

 7000 feet altitude in Mexico. It is perennial, resembling the cot- 

 ton plant so closely that it is locally known as wild cotton. 



Entomologically Thurberia is a very interesting plant. The 

 large nectary of the midrib on the underside of the leaves, the three 

 nectaries at the base of the involucral bracts, and the nectar of the 

 flowers prove powerful attractions to insects. The tender foliage 

 and the succulent buds and bolls furnish excellent insect food. 



BOLL WEEVIL. 



By far the most important species attacking the wild cotton is 

 the boll weevil, Anthonomus grandis, var. thurberice Pierce which 

 is known to breed in the squares and bolls in Ventana and Sabino 

 Canyons of the Santa Catalina Mountains, and Sawmill and Stone 

 Cabin Canyons of the Santa Rita Mountains. It passes the winter 

 spring and summer in cells in the bolls, emerging in August or as 

 late as September 1 to begin attack on the new crop of squares 

 and bolls. It hardly seems possible that the weevil can have more 

 than two generations a year on this plant. The eggs are laid at 

 the base of squares, and are covered by a transparent gelatinous 

 scale upon which is usually a little clot of excrement. The eggs 

 are elongate, often twice as long as wide. On August 25 in Stone 

 Cabin Canyon no larva? were found over one-fifth grown, although 

 it is quite possible the weevil may develop earlier in the lower 

 canyons. The first adults were bred from Stone Cabin Canyon 

 bolls about November 10. 



The adult weevils are robust and generally larger than the Mexi- 

 can cotton boll weevil and one receives a very strong impression 

 that he is dealing with a distinct species. The records made by 

 Mr. Coad at Victoria, Tex., however, have proven the Arizona form 

 to be conspecific with the cotton boll weevil. The typical grandis 

 occurs at altitudes under 2000 feet, while thurberiw is found only 

 at altitudes of over 4000 feet. The food plants are considered 

 generically different by botanists. Geographically the two vari- 

 eties are separated by hundreds of miles. The cotton weevil 

 occurs in Cuba, Costa Rica, Mexico and the southern United 

 States while thurberice occurs in southern Arizona and also prob- 

 ably in the mountains of Mexico. 



