30 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



Gonopods short. Claw short and pale; basal spines 2+2 but small, 

 the inner one commonly a short point. 



Length of body 8-8.4 mm.; width 1.2 mm.; length of antennae 

 4.6 mm. ; of anal legs 4-4.3 mm. 



Agenitalis Stage I. Color yellowish brown, head darker. Legs 

 and antennae smoky white. 



In the one specimen of this stage obtained the forty articles of 

 the antennae are already present, the individual doubtless being 

 exceptional in this regard. 



Prosternal teeth minute or obscure. 



Ocelli distinct; considerably larger than in the following stage. 



Gonopods appearing merely as incipient buds. 



Coxal pores 2, 2, 2, 2, 2. 



Length of body 5.5 mm. ; width .65 mm.; length of antennae 2. 5 mm. 



Pullus Stage IV. Last three pairs of legs appearing as pale ap- 

 pressed buds. 



General color yellowish. Antennae and legs white. 



Ocelli small; colorless. 



Coxal pores 1, 1; very small. 



Length of body 3-4.6 mm. ; length of antennae 2.1-2.5 mm. 



LOCALITIES. Utah (in the Wahsatch Mts., chiefly at elevations 

 from 6,000 up to 10,000 feet above sea-level. Farmington Canyon I 

 City Creek Canyon! Mill Creek Canyon! NefFs Canyon! Little Cot- 

 tonwood Canyon ! Big Cottonwood Canyon ! American Fork Canyon I 

 Spanish Fork Canyon! Also in/Uintah Mts.!); California (Truckee! 

 in the Sierra Nevada). 



In the Wahsatch Mts. the species is found at the upper elevations 

 under wood and stones along streams, about springs, and near melting 

 snow, and is not uncommon under the fallen logs of coniferous and 

 quaking aspen woods away from running water. It prefers especially 

 cool and humid situations. 



ZYGETHOBIUS SOKARIENUS Chamberlin. 

 Can. entom., 1911, 43, p. 382. 



DIAGNOSIS. Dorsum reddish brown to chestnut, with head and 

 ultimate segments darker; head uniform in color; legs brown, paler 

 distally, the posterior pairs darker. Head subrotund, longer than 

 wide; widest in front of middle; sides but moderately convexly bulg- 

 ing. Body about eight times as long as width of tenth plate; strongly 



