1170 
Journal of Agricultural Research 
Vol. XXVIII, No. 12 
The description above given applies to a bee larva four or five days old, after 
removal from the cell. The larva is never permitted to assume this form, how¬ 
ever, until after the cell is sealed, when it undergoes the important changes pre¬ 
liminary to pupation. The actual shape assumed by the bee larva of from four 
to five days old is shown in Plate 1, E. The specimen from which this drawing 
was made was fixed and hardened in the normal position in the cell, from which 
it was afterwards extracted. As can readily be seen, the larva is bent ventrad 
in the shape of the letter U, head and anus being brought close together, and fits 
its narrow quarters so completely and so snugly that it forms a veritable cast of 
the interior of the cell, the prismatic six-sided form of the latter being plainly 
reproduced by the larva, which not only takes nourishment and grows in this 
compressed state, but on being withdrawn from the cell can immediately assume 
the plump, rounded form shown in figure 1, the only remaining perceptible 
evidence of its close confinement being a slight asymmetry of the 8th abdominal 
segment, the lateral fold on this segment being more turgid on the side turned 
toward the bottom of the cell. This is evident in Plate 1, E. In all the speci¬ 
mens of larvae fixed and hardened within the cell the head lies somewhat closer 
to the mouth of the cell than the anus, the long axis of the larva thus being 
spirally curved. In some larvae the right side is outermost, in others the left. 
Kellogg {24) has given a brief account, accompanied by two figures, of the 
head and mouth parts of the honeybee in connection with a study of the meta¬ 
morphosis. It is of interest to note here that the spines on the maxillae were 
found to represent the minute one-segmented maxillary palpi of the adult. 
This may readily be seen in stained and cleared preparations of the head of 
larvae about to pupate. Kirmayer {26) has given a detailed account of the 
structure of the head of Vespa in connection with the changes taking place dur¬ 
ing the metamorphosis. Kirmayer’s excellent figures of the head of the larva 
of Vespa show that while it is similar to that of the honeybee, it differs much in 
details, and particularly in the proportions of the various parts. It may be 
noted that in general the head of the larva of Vespa is both shorter and narrower 
than that of the bee larva, the labrum being indented ventrad and even a trifle 
caudad. (PI. 10, A.) The labium is relatively much smaller, while the head 
capsule lacks the conspicuous median dorsal cleft seen in the honeybee. 
HYPODERMIS AND CUTICLE 
The hypodermis, which, together with the cuticle secreted by it constitutes 
the body wall, is a simple one-layered epithelium, differing in thickness in different 
parts of the larva. These differences are* indicated in many of the illustrations, 
but it may be said that in general both hypodermis and cuticle are thin over the 
entire extent of the trunk, the hypodermis being as a rule thinner at the middle 
of the segments and increasing in thickness in the intersegmented regions, and 
therefore ranging from the squamous to the cuboidal type. In the head the 
hypodermis has a considerably greater average thickness than in the trunk 
(PL 2, B, and 3, D). The hypodermal cells here have as a rule a prismatic form, 
and are in many places so slender and so closely crowded together that the nuclei 
are compelled to lie at different levels, giving the impression of a many-layered 
epithelium. It should be noted that in the larva there is no thinning of the 
hypodermis or cuticle at the borders of the segments or at the bases of the mouth 
parts. Such a thinning would correspond to the articular membranes of the 
imago. 
The rudiments of the antennae, wings, legs, and genitalia remain to be men¬ 
tioned, since they are hypodermal structures. The antennal rudiments of old 
larvae are ovoid in form and are situated in deep depressions or cavities (peripodal 
