June 21, 1924 
Morphology of the Honeybee Larva 
1173 
SoeGng 
VNC 
deu to cerebrum, olfactory or antennal lobes ( AntL ), and the la'rge protocerebral 
lobes ( IBr ). Laterad and caudad the protocerebral lobes merge into the broad 
auriculate optic lobes ( OpL ), which lie almost precisely in the transverse plane. 
Their edges are quite thin and their posterior faces almost perfectly flat. The 
two lobes of the tritocerebrum are recognizable externally as distinct swellings 
most evident in profile 
view (PI. 1, C, 3Br); 
those of the deutocere- 
brum, however, are to be 
identified externally only 
by the antennal nerves 
which spring from them. 
On the anterior faces of 
each of the optic lobes, 
near their ventral mar¬ 
gins, and involving also 
the antennal lobes, is a 
well-marked depression, 
of a somewhat hemi¬ 
spherical outline. These 
depressions are produced 
by the peripodal cavities 
of the antennal rudi¬ 
ments, which in mature 
larvae are of large size. 
Two pairs of nerve 
trunks arise from the 
brain. The first of these, 
the antennal nerves (PL 
1, B and C, AntNv) 
spring from the antero¬ 
lateral faces of the anten¬ 
nal lobes. They then 
take a lateral course to 
the base of the antennal 
rudiment, where each di¬ 
vides to form three 
branches. Two of these 
branches innervate the 
adjacent masses of meso¬ 
dermal cells surrounding 
the base of the antennal 
rudiment, and are there¬ 
fore evidently motor 
nerves. The third or 
sensory branclTenters the 
cavity of the antenna 
and passes along its lat¬ 
eral margin, sending off 
a tuft of nerve fibers to each segment. This is well illustrated by Plate 2, D, 
which shows the antennal rudiment in longitudinal section with the nerve (AntNv) 
giving off branches to each of the six segments seen in the section. The labro- 
frontal nerve (PL 1, B and C, and 2, B, LmNv) springs from the anterior face 
of each of the two halves of the tritocerebrum. This nerve is, as its name 
-Gng8"l l 
Fig. 1.—Nervous system and ventral body wall of mature honeybee 
larva, drawn from a dissection. X16 
