1961] 
Causey — A drityla 
135 
seen unless leg 1 1 is removed. The coxite is elongated, broadened 
and rounded distad, smooth on the anterior surface, and thickly setose 
over part of the more complex posterior surface; a subapical flange 
is on the ectal surface, and near the base of the mesial surface is a 
large perforation through which the enlarged, soft coxal sac projects. 
The coxal sac is contiguous with its homologue in the midline. The 
sternum is divided and coalesced with the coxa, forming a thick, short 
coxosternum which is contiguous with its homologue along a movable 
suture; the inconspicuous spiracles open on the ectal surface of the 
coxosternum. 
Appendages 7 2 and 8 1 (the posterior gonopods and legpair 10, 
respectively) fit close together, but there is no fusion, and with 
careful dissection they can be completely separated. 
In the female, the setae on the vulvae are unusually long. The 
legs are typical of the family. 
Emendations. In the original description, Chamberlin (1910, p. 
236) incorrectly interpreted the coxites of legpair 10 (8 1 ) as part 
of the) anterior (7 1 ) and posterior (7 2 ) gonopods. The correct legends 
of plate: 31, figures 4-7 are: figure 4, legpair 10, caudal aspect; fig- 
ure 5, anterior gonopods and parts of posterior gonopods and legpair 
10, cephalic aspect; figure 6, left gonopods and tenth leg, lateral 
aspect; posterior gonopods, cephalic aspects. Only legpairs 4 and 5 
were represented (PL 32, Figs. 2-6) as having a small lobe on the 
mesioproximal surface of segment 4. I have found that legpairs 3 
through 7 have segment 4 similarly modified ; possibly there is some 
variation of this character. A large promentum was indicated in 
plate 32, figure 7. There is no promentum; the small triangular 
space anterior to the mentum is covered only by a membrane. 
Variations. The ventral margin of the anterior gonopods is irreg- 
ularly serrated in each of the 4 male specimens that I have examined. 
The serrations vary between 3 and 14 or 15. A possible variation in 
the lobation of the pregonopodal legs was mentioned in the preceding 
paragraph. 
Material Examined. UTAH : Mill Creek Canyon, Salt Lake Co., 
larvae (MCZ) [? metatypes]; South Willow Canyon, Tooele Co., 
Figures 3, 4. A drityla deseretae (Chamberlin). 3. Posterior gonopods and 
left tenth leg, anterior view. 4. Left posterior gonopod and legpair 10, poste- 
rior view. (Abbreviations: A7 1 , A7 2 , A8 1 , sternal apodemes of anterior 
gonopod, posterior gonopod, and leg 10, respectively; C7 2 , C8 1 , coxites of 
posterior gonopod and leg 10, respectively; F, PF, femur and prefemur of 
posterior gonopod, respectively; S7 1 , S7 2 , S8 1 , coxosternites of anterior gono- 
pod, posterior gonopod, and leg 10, respectively; T, telopodite of leg 10.) 
