NORTH AMERICAN BOSTRICHIDAE 41 



out a distinct row of teeth along lateral margins; surface sparsely 

 clothed with long, recumbent yellowish hairs, sparsely, rather densely 

 punctate at sides, coarsely imbricate at middle on basal half, the im- 

 brications narrow and narrowly rounded at apices, and with trans- 

 versely arcuate rows of elevated teeth at middle on apical half, the 

 teeth obtusely rounded at apices, and distinctly separated from one 

 another, except the two median ones on anterior margin, which are 

 nearly contiguous. 



Elytra at base subequal in width to pronotum at basal third ; sides 

 parallel, conjointly broadly rounded at apices ; surface rather coarsely, 

 densely punctate, the punctures arranged in more or less distinct 

 rows, sparsely clothed with long, recurved, yellowish hairs, which are 

 twice as long as the intervals between punctures on anterior part of 

 disk; apical declivity sparsely clothed with short, erect, yellowish 

 hairs, without tubercles, coarsely, sparsely, irregularly punctate and 

 distinctly granulose in both sexes. 



Body beneath sparsely clothed with rather long, recumbent, yel- 

 lowish hairs; abdomen sparsely, shallowly punctate, and finely, 

 densely granulose. 



Length 3-5 mm., width 1-1.6 mm. 



Type locality. — Santa Rita Mountains, Ariz. ; type in Paris 

 Museum. 



Distribution. — From material examined : 



Arizona: Santa Rita Mountains, 3,000 to 4,000 feet, June 15, 1924 (C. T. Vor- 

 hies) ; Stone Cabin Canyon, Santa Rita Mountains, August 25, 1913 (W. D. 

 Pierce) ; French Creek (E. A. Schwarz), Sabino Canyon, Santa Catalina Moun- 

 tains, November 28, 1913, reared (H. S. Barber) : Fish Creek, 2,300 to 3,000 

 feet, December 16, 1913, reared (Schwarz and Barber). 



Canal Zone: Paraiso, February 11, 1911 (E. A. Schwarz) ; Panama, December 

 1911 (A. Busck). 



Mexico: Hacienda Hormiguera, Torrion, Coahuila, April 10, 1922 (Hunter No. 

 9099). 



Host. — All the specimens examined from Arizona were reared from 

 or collected on wild cotton {Thurberia thespesioides Gray). A nice 

 series of specimens was reared from dead twigs of this plant by H. S. 

 Barber and E. A. Schwarz. One specimen was taken in a dry stem 

 of cultivated cotton in Mexico. 



Lesne (1930) described this species from two specimens collected by 

 C. T. Vorhies, and specimens have been examined by the writer from 

 the original set. This is a valid species, but many of the characters 

 given by Lesne to distinguish it from truncatus are found to be vari- 

 able when a good series of specimens are available for study. In a 

 large series of specimens of apax and truncates examined from Ari- 

 zona, Mexico, and Central America, the body of apax is not more elon- 

 gate, the sculpture on the pronotum and elytra are not more distinctly 

 sparser or shallower, the last segment of the antenna is not narrower, 

 and the cuneiform tubercles near the posterior margin of the pronotum 

 are not more elongate than in truncatus. In truncatus the lateral 

 margins of the pronotum near the posterior angles are marked with a 

 row of distinct teeth, whereas in apax these are absent or at the most 

 only vaguely indicated. In truncatus the hairs on the elytra are short 

 and recurved, and on the anterior part of the disk are about as long as 

 the intervals between the punctures, whereas in apax the hairs are 

 considerably longer, at least twice as long as the intervals, but in both 



