Nov. io, 1913 
A Cotton Boll Weevil in Arizona 
93 
Mule Pass, Huachuca, and Chiricahua Mountains, and also in Fish Creek 
Canyon of the upper Salt River valley, and at Dragoon, Fort Bowie, 
and Davidson Springs, all in Arizona. 
Thurberia grows at altitudes from 2,250 feet to 7,000 feet, and is found 
in the bottom of the canyons, on the canyon walls, and on top of the 
ridges, growing usually where protected more or less from the greatest 
heat of the sun. 
The plant begins flowering in some localities in July, but in others it is 
just beginning to bud in the latter part of August. Flowering continues 
into October. 
In appearance Thurberia is so nearly like cotton that the Mexicans and 
natives call it “wild cotton.” The leaves are simple, or 3 or 5 lobed, 
and in the two latter forms resemble the okra-like form of Upland cotton 
{Gossypium hirsutum) or the normal leaves of the Mexican species Gossy- 
pium palmeri Watt, and G. schottii Watt. The leaf has a nectary on the 
Fig. 6.— Anthonomus grandis Boh.; 
Antenna of female. Much en¬ 
larged. (Original.) 
Fig. 5.— Anthonomus grandis , var. 
thurberiae : Antenna of female. 
Much enlarged. (Original.) 
midrib, like cotton, and this nectary is as attractive to insect life as the 
leaf nectaries of Egyptian or Upland cotton. The buds differ from cotton 
buds by the truncate calyx cup and the linear involucral bracts, but the 
three nectaries, which also prove a great attraction to insects, are present 
as on cotton squares. The flowers resemble cotton flowers very closely. 
The bolls are small, not over three-fourths of an inch in length, and are 
3 to 5 celled, with two rows of seed in each. There is a very tiny fiber 
on the cell walls. 
The plants are perennial, growing to be over 10 feet high, with a spread 
of about 10 feet, and having a large, strong, woody trunk. They are 
very prolific fruiters. The species is often killed back by frosts, as is 
evidenced by the dead terminals with the old bolls of previous seasons. 
The heavy wash in the mountain canyons is one of the principal means of 
dispersion of the plant. 
Thurberia is exceedingly like cotton in most essentials, the relationship 
being most clearly demonstrated by the many insects which attack both. 
