June 21, 1924 
Morphology of the Honeybee Larva 
1205 
only the peripheral ends of the rudiments projecting above the surface of the 
head. The peripodal cavities of the antennae as well as of the other appendages 
are closed externally only by cuticle. The wing rudiments are small, flat, heart- 
shaped, hollow outgrowths of the hypodermis situated in shallow depressions 
low down on the second and third thoracic segments. The leg rudiments are 
ovoid in shape and are situated in deep peripodal cavities on the ventral side of 
"the three thoracic segments, close to the mid-line. The genital rudiments are 
six in number, one pair being situated on the 8th abdominal segment and the 
other two pairs on the 9th. They are knob-like in form and lie in shallow open 
•depressions. 
(3) The rigidity of the head capsule is increased by the tentorium, which con¬ 
sists of a system of tubular ingrowths of the hypodermis lined by chitin. It 
comprises two short and broad posterior arms which are attached to the cranial 
wall at the junction of the lateral furrows with the neck fold; a transverse central 
body, continuous with the lateral arms; and two slender anterior arms joining the 
ends of the central body to the cranial wall at the sides of the clypeus. On the 
lateral face of each of the anterior arms is a spine for the attachment of a muscle. 
At the base of each of the mandibles, on its mesial side, is a hollow spine-like 
apodeme for the insertion of the adductor muscle. 
(4) The nervous system is simple and primitive as compared with that of the 
•adult and consists, in the mature larva, of a brain, a nerve chain comprising 11 
ganglia joined by paired connectives and a stomatogastric ganglion with its 
accompanying nerves. The brain includes a pair of large somewhat crescentic or 
auriculate optic lobes, situated in the transverse plane, well-developed protocere¬ 
bral lobes, and small antennal lobes (deutocerebrum) and tritocerebral lobes. 
The two halves of the latter are united by a distinct suboesophageal commissure 
which is not fused with the suboesophageal ganglion. Two pairs of nerves 
spring from the brain proper: the antennal nerves, which connect the antennal 
lobes with the antennal rudiments, and the labrofrontal nerves, which spring 
from the tritocerebral lobes. Each of these last mentioned nerves divides near 
its point of origin into the frontal nerve, which runs mesiad to the frontal gang¬ 
lion, and the labral nerve, which innervates the labrum. The suboesophageal 
ganglion, attached to the brain by slender crura cerebri, is somewhat lenticular 
in form, broader at its anterior end. It represents three pairs of simple ganglia 
and gives rise on each side to four nerves: mandibular, maxillary, labial, and the 
X-nerve of Jonescu. The last mentioned possibly corresponds to the salivary 
gland nerve in other insects. In the bee larva it is difficult to trace but appears 
Ik) terminate in the superficial hypodermis at the base of the labium. The 11 
ganglia of the ventral cord are lenticular in form and are connected with one 
another by distinct parallel connectives. The ganglia are not located in the 
middle of the segments but are near their anterior ends. The three thoracic 
ganglia are the largest, those of the following seven abdominal segments being 
subequal; the 8th abdominal ganglion is, however, elongate and comprises 
three pairs of simple ganglia and the rudiment of a fourth. All of the abdominal 
ganglia are provided with well-developed lateral nerves which divide into branches 
supplying the viscera, muscles, etc. The stomatogastric system comprises a 
well-developed stomatogastric ganglion situated above the pharynx and con¬ 
nected to the brain by the frontal nerves. Anteriorly it gives off a single nerve, 
the superior pharyngeal nerve, supplying the superior pharyngeal muscles and 
the tip of the labrum. Posteriorly the stomatogastric ganglion gives off a stout 
nerve which passes caudad, diminishing in caliber meanwhile, along the dorsal 
surface of the oesophagus. It finally breaks up into small branches. 
The nervous system of the larva is histologically similar to that of the imago 
but is of course less specialized. The central nervous system displays the usual 
