182 
Psyche 
[Dec. 
located ; pleurites four and five are less elongate and are 
progressively less attenuated anteriorly, the dorsal mar- 
ginal setae are longer than the ventral ; pleurite six is nar- 
row and tapers anteriorly ; the seventh plenrite is narrow 
and very blunt anteriorly ; in the sixth and seventh pleu- 
rites the chitinized area at the base of the marginal setae 
is progressively more isolated from the anterior and 
major portion of the pleurite, and the marginal setae are 
greatly elongated, the ventral ones being somewhat longer 
than the dorsal. 
Tergal and sternal plates of the abdomen are well chi- 
tinized and cover most of the surface area, the anterior 
plate of each segment tending to be larger than the pos- 
terior; on their posterior margins most of the tergites 
have from eight to thirteen setae and most of the sternites 
have from six to ten ; however, there is considerable varia- 
tion in these numbers. The first abdominal sternite is 
much wider than the second, is pointed anteriorly and 
concave posteriorly; the second abdominal sternite is 
almost a half circle; the third is more than twice the 
width of the second and has a pointed anterior margin. 
Between the ends of the posterior plate and the corres- 
ponding pleurite on the fourth to seventh segments dor- 
sally and the third to seventh ventrally, there is a single 
seta of moderate length. Ventral to and parallel with 
the posterior margin of the seventh pleurite, a small plate, 
bearing three setae on the posterior margin, has a lobe di- 
rected anteriorly from its lateral half. 
Male (Fig. 1, B). Length 0.8-1.0 mm. As described 
by Ewing, except for the following modifications and ad- 
ditions. Sternum usually longer than it is broad and 
may sometimes overlap the second and third coxae. 
Tergal and sternal plates of the abdomen are well de- 
veloped. The first large tergite is usually strongly con- 
cave and irregular along its anterior border ; the second, 
third, and fourth tergites progressively increase in length 
and are convex anteriorly; the fifth, sixth, and seventh 
tergites are progressively reduced in size and only in a 
narrow zone near their anterior margins are they strongly 
