Characters in Paratrombium — Newell 
face (Fig. 71). The posterior wall of the 
urstigma lies in a slitlike pouch between the 
posterior margin of coxa I and the overlying 
membranous cuticle of the ventral body wall. 
An apodeme arises from the anterior margin 
and extends in an anterior direction. The 
punctate cuticle posterolateral to the urstigma 
in Figure 73 is the upturned margin of coxa I 
which continues directly with the striated 
membranous cuticle of the body wall. Al- 
though the function of the urstigma is not 
apparent from this, it obviously is not a 
respiratory opening. The term "urpore” is a 
misnomer, but "urstigma” appears to be ac- 
ceptable as long as it is understood that it is 
not a "stigma” in the sense of a respiratory 
opening. Details of lateral portion of pro- 
podosoma as shown for P. bidactylus (Fig. 34). 
Base of gnathosoma as described for P. 
bidactylus , except that the supracoxal setae 
appear to be consistently more lateral in po' 
sition, and also shorter and blunter. Palpi as 
in previously described species, except for 
chaetotaxy of tarsus. The tarsus bears four 
long setae dorsally, one of which is very 
slender, another heavy and scythe-shaped, 
and the other two intermediate in form. The 
two ventral setae are flexible and very elon- 
gate. Between the four dorsal and two ventral 
setae is a transverse row of four short, peglike 
setae. One of these is presumably the solen- 
idion, probably the most posterior one, but 
all four are so similar in form and size that it 
is impossible to say for certain which one is 
the true solenidion. Podocephalic canals very 
short, extending scarcely to the level of the 
anterior margin of coxa I. Rostrum as in 
P. bidactylus. 
Although the larva of P. bidactylus is larger 
than that of P. quadriseta , its palpal tarsus ap- 
pears to be both actually and relatively 
smaller. In one specimen of each of the two 
species, the maximum diameter of the base of 
the tarsus measured 10 and 13 /x respectively, 
which is a considerable difference in a struc- 
ture of this small size. In P. quadriseta , four 
small setae can be resolved with little or no 
369 
difficulty, arranged in a straight row across 
the distiventral surface of the tarsus. In P. 
bidactylus on the other hand, only two setae 
can be seen with any certainty here, and these 
are noticeably compressed between the bases 
of the larger setae and the tarsus (Figs. 
35, 67). 
Femora I— III undivided, basiventral seta of 
all femora very delicate, only about half the 
diameter of the other setae on the segment. 
Chaetotaxy of legs similar to that of P. bi- 
dactylus, at least so far as the number of setae 
on the various segments is concerned. Solen- 
idia of patella I at .37ff and .54 ff, vestigial 
seta at .80 d. Tibia I with solenidia at .50 d 
and .74ff, a vestigial seta at .88 d. Tarsus I with 
solenidion at .35-48 ff, e d at .64-71, and e p 
at 0.94, famulus at .38 — .55. Patella II with a 
single solenidion at .40, vestigial seta at .73; 
tibia with two solenidia, at .39 d and .6ld. 
Tarsus II with solenidion at .40-. 5 Off, famulus 
at .35-.49ff; eupathidia lacking. Patella III 
with solenidion at .47, tibia without solenidia. 
Tarsus III typically bears four whorls of 
normal setae containing three, four, four, and 
two setae each (total 13), but of 8 tarsi ex- 
amined, two had 14 normal setae and one had 
12 normal setae. The basal whorl normally 
contains only three setae, but in exceptional 
specimens a fourth has been added. In that 
tarsus III with only 12 setae, the deletion 
occurred in the third whorl from the base of 
the tarsus. Tarsi I and II each has three 
well- developed claws, the median one more 
delicate and erect than the anterior and pos- 
terior claws. Tarsus III with anterior and 
median claw well developed, posterior claw 
as in P. bidactylus , reduced to a very minute 
rudiment. 
type locality: Riverside, California, Santa 
Ana River, at Camp Evans. Females found 
crawling on muddy bank of stream, April 23, 
1955. Collected by the writer. 
remarks: The correlation between the 
larva and adult of this species was established 
by rearing. This species is obviously closely 
related to Paratrombium bidactylus , but the dif- 
