78 Journal New York Entomological Society. [Voi. v. 
are more exserted and prominent, the last tergite being much more pro¬ 
duced than in Vespa. The nervous system is nearly the same in the 
middle of the body, but owing to the shorter segments the ganglia are 
nearer together, and each ganglion is opposite each suture; the size of 
the ganglia and of the cords are the same, but the ganglia appear to be 
a little farther separated than in Vespa, in the specimens examined. 
The head is very large, round, short and broad, full, convex above. 
The eye-slits are long, narrow, oblique and prominent. The antennal 
tubercles are flat, depressed, large and conspicuous, and are placed on 
each side of the clypeus and in a line with the anterior or lower end of 
the eyes. The clypeus is large, very regularly equilaterally triangular, 
the apex or posterior portion separated by a slight suture from the ante¬ 
rior and much -larger portion : the front edge is straight and aligned with 
the squarely docked front edge of the side of the head. Labrum very 
broad and short, nearly as broad as the clypeus is long; the front edge 
is straight, the sides well rounded; rounded, swollen, full and very prom¬ 
inent at the end. Mandibles broad, triangular, very acutely bidentate, 
much shorter and broader at base than in the Apidae, very convex on the 
outer side. Maxillae large, full, swollen, with two small corneous tu¬ 
bercles on the interior next the mouth. Very full and bulging exter¬ 
nally. Labium well separated from the mentum by a distinct suture, 
with two terminal tubercles. Mentum broad, low, triangular, not quite 
reaching to the outer side of the maxillae, but nearly as broad as the 
head. 
It differs from the larva of Vespa in having the antennal tubercle a 
little more approximate, the clypeus more regularly triangular and more 
distinct, while the labrum is very much larger and excessively swollen. 
The mandibles are very different from those of Vespa, being bi¬ 
dentate, very acute, broad at base, triangular, while in Vespa they are 
tridentate, oblong, and as wide at the tip as at the base, the teeth being 
rather equal and blunt, while the mentum is not prominent. The en¬ 
tire head is freer from the body in Polistes, and harder, more corneous 
than in Vespa. 
Both Polistes and Vespa larvae differ from those of Bombus and 
Apidae in general in having the clypeus and mouth-parts larger; by the 
antennal tubercles being more distinct, by the presence of the eye-slit, 
by the larger mandibles and maxillae, while the entire head is larger in 
proportion to the rest of the body, and the surface of the segments are 
smooth. The end of the body is more acute, and the lateral ridge less 
marked. (In the larva of Pompilus, the segments are more thickened 
