70 PROCEEDINGS OF THE ACADEMY OF [March, 



pattern, yet in short yellow grass, or tufted bunch grass, the spe- 

 cies is not easy to locate, often never being seen unless marked 

 down after a flight. It is distinctly a hillside species, rarely found 

 on dirt hills, but with a strong preference for stony or rocky slopes, 

 with scattered cover of short grass or bunch grass, and dotted 

 with lecheguilla {Agave lechiujuilla) , agaves {Agave schotti and 

 palmeri), bear grass {Nolina microcarpa) , ocotillo {Fouquieria 

 splendens), sotol {Dasylirion leiophyJIum and wheeleri) and cacti. 

 Near the upper limits of its vertical distribution it occurs in the 

 open spots of scrub oak areas. In southern Arizona it is a species 

 of the Desert and Encinal regions, as they have been delimited 

 by Shreve.21 In but a single case have we noted the species in 

 flat land, then at Marathon, Texas, where two were seen on the 

 plain some distance from the hills where individuals of the species 

 were numerous. 



The species has been taken adult as early as June 10 to 12 (Chisos 

 Mountains, Texas) and as late as November (El Paso, Texas, 

 and Lerdo, Durango, Mexico). The latest exact date we have 

 is October 14 (Rock House Canyon, Arizona), immature indi- 

 viduals in the stage preceding maturity being taken as well as 

 adults. It is possible the species matures earlier and persists later 

 in the season southward at lower elevations than toward the north- 

 ern limit of its range, or at higher elevations southward, but the evi- 

 dence is not fully conclusive. The earliest records we have for 

 northern New Mexico are August 10 (Las Vegas Hot Springs) 

 and August 12 to 20 (Jemez Hot Springs), while we have adults 

 from the border region taken from July 9 (Franklin Mountains, 

 Texas) and 18 (Mud Springs, Arizona") on. However, we have a 

 single adult male from Prescott, Arizona, taken July 7, and a 

 good series of both sexes from the same locality, taken from July 9 

 on. The latest date for immature specimens in the Prescott 

 series is August 5, while we have adults taken as late as August 25. 

 At Pine Mountain, Davis Mountains, Texas, elevation 5800 to 

 7000 feet, we found both adults and immature specimens common 

 on August 31, which shows a late maturing season at an elevated 

 locality in a relatively southern region, while, as stated above, 



2' Publ. 217, Carneg. Inst. Wash., po. 15-29, (1915). 



2- The occurrence of adults so early, at a locality relativelj^ .so high (6800 feet), 

 can be explained, we are certain, by slope exposure. The locality is on a warm 

 south-facing slope, at the upper edge of the Encinal region. Shreve (Publ. 217, 

 Carneg. Inst. Wash., p. 97 et seq., (1915)) has carefully analyzed the role of 

 slope exposure in the Santa Catalina Mountains. 



