1914.] NATURAL SCIENCES OF PHILADELPHIA. 113 



lijiht may be a factor in determining the intensity of the color pat- 

 tern, the percentage of intensive specimens being greatest from those 

 locaHties known to us where tjie cover is densest, more light resistant 

 and the surface conditions less favorable for reflecting light. 



Distribution. — This species has the widest distribution of any in 

 the genus, its range extending from southern New Mexico (Sacra- 

 mento Mts.), south to southern Coahuila, Mexico (Jaral), west to 

 the Baboquivari Mts., central southern Arizona, and east to the 

 Texas coast at Gregory (San Patricio Co.). Its vertical range is 

 from practically sea-level at the last-mentioned locality to -as high 

 as -1,800 feet in the Sacramento Mountains. Its zonal range appears 

 to be entirely Lower Sonoran. As far as known, it does not extend 

 into the region of the Edwards Plateau in central Texas and does 

 not occur in the mountains of Trans-Pecos, Texas. Scudder in his 

 original description stated that he had specimens from Mexico, this 

 probably referring to the Montelovez specimens examined by us, as 

 these were contained in his collection. 



Biological Notes. — The present species was fairlj^ numerous on 

 creosote-bush {CoviUea tridentata) at Dry Canyon, Sacramento 

 Mountains, New Mexico, and occurred on the same plant onTumamoc 

 Hill, Arizona, while at the latter locality it was also found on the 

 ground in short, dry, yellow grass. On the slopes of Sycamore Canyon, 

 Baboquivari Mountains, Arizona, it also occurred in grasses and was 

 taken from Acacia sp. At Marathon, Texas, it was generally common 

 in various low bushes and grasses, the males, particularly, often 

 sprawled out in a loose manner somewhat reminding one of phalangids 

 or harvest-men, while at Kent and Garden Springs it occurred in 

 similar situations. At Beeville and Uvalde it was taken from green 

 weedy plants, at Gregory it was found in the green tangle about a 

 mesquite clump, Avhile it was beaten from a low bush on a sandy 

 slope at Laredo. At Laguna del Gato it was taken rather commonly 

 with D. castanea on a low, very green rliamnaceous shrub (probably 

 Condalia ohovata). 



A correlation of the dates on the present serie? brings out some 

 very interesting points on the time of maturity of the species. The 

 earliest dates on which adults were secured are Jul}' ,28 at Beeville, 

 July 30 at Gregory, August 6 at Laguna del Gato, August 7 at Mesilla, 

 August 10-12 at Laredo, and August 16 at Mesilla. At Dry Canyon, 

 New Mexico (elevation 4,800 feet), on July 13 nymphs not more than 

 half grown were not uncommon, while at Marathon and Garden 

 Springs on August 26-27 and September 2, respectively, nothing but 

 8 



