124 
Psyche 
[December 
lateral bosses on each somite. Segmentation distinct. Body 
hairs moderately numerous and uniformly distributed; 
hairs short (0.035-0.15 mm), with short-bifid tip. Other- 
wise similar to the mature larva. 
Very young larva: Length about 2.4 mm. Subcylindri- 
cal, but somewhat constricted at the mesothorax and meta- 
thorax. Anus terminal. Body hairs moderately numerous, 
except for large naked intersomitic areas; with short-bifid 
tip, short to moderately long (0.035-0.105 mm). Head hairs 
simple. Otherwise similar to the young larva. 
Material studied: numerous larvae from British Guiana. 
Genus Orectognathus F. Smith 
Shaped somewhat like a crookneck squash; thorax and 
first abdominal somite curved ventrally; diameter greatest 
at abdominal somite V, decreasing gradually toward the 
anterior end and more rapidly toward the posterior end, 
which is broadly rounded. Body hairs moderately nu- 
merous. Of three types: (1) short to moderately long, 
bifid, with the branches equal, short to long, denticulate 
and recurved at the tip, the most abundant type; (2) on 
the ventral surface, short to moderately long, slightly 
curved, distal half denticulate, usually with a minute hook 
at the tip; (3) a few on the dorsal and lateral surfaces 
of each somite, long, sparsely denticulate, with a minute 
hook at the tip and a short denticulate lateral branch near 
the base. Antennae moderately large, with two or three 
sensiila each. Head hairs short to long, fiexible, with a few 
Explanation of Plate 8 
Orectognathus clarki Brown, Figs. 1, 2 and 4-10. — 1, head in anterior 
view, X67 ; 2, larva in side view, X20; 4, long body hair with unequal 
branches, X235; 5, denticulate body hair, X235; 6 and 7, body hairs 
with equal branches, X235; 8, left mandible in anterior view, X185; 9, 
left maxilla in anterior view, X185; 10, left maxillaiy palp in anterior 
view, X730. 
Orectognathus satan Brown, Fig. 3, labium (left half of drawing shows 
posterior view, right half, anterior view), X235. 
Clarkistruma alinodis Forel, Figs. 11-15. — 11, mandible in anterior 
view, X185; 12, head in anterior view, X105; 13, larva in side view, X37: 
14 and 15, two types of body hairs, X185. 
