The Life Processes of the Individual 143 
for criticism. There have been, however, very few in¬ 
vestigations of the digestive processes. The digestion of 
insects is discussed by Biedermann, 1 and more recently 
Petersen 2 has published a discussion of the processes of 
digestion in the honeybee. This is the first good paper on 
this subject and the author is to be commended for taking 
a stand against the making of comparisons with human 
physiology. 
The mouth parts have already been described (p. 135), 
and those glands (1GI, Fig. 59) which are supposed to be 
concerned in the production of larval food have also been 
discussed (p. 111). Behind the mouth is an enlargement 
of the alimentary canal called the pharynx ( Phy , Fig. 60), 
leading to a long narrow tube extending through the thorax, 
the oesophagus ((E). Behind the constriction between 
the thorax and abdomen, the alimentary canal widens to 
form the honey-stomach (IIS), homologous to the crop of 
other insects. This is a thin-walled, muscular organ used 
by the worker in carrying nectar to the hive. Behind the 
honey-stomach is a valvular structure, the proventriculus 
(Pvent, the anterior part being often called the stomach- 
mouth) which separates the honey-stomach from the ven- 
triculus (often called the chyle stomach). The proven¬ 
triculus is of special interest in the bee, since when closed it 
prevents the nectar from mixing with the contents of the 
ventriculus and makes it possible for the honey-stomach to 
function as a carrying vessel. It is claimed by Schonfeld 
that the anterior end of the proventricular valve (nn, Fig. 
61) may be moved forward to touch the posterior end of 
the oesophagus, so that the contents of the ventriculus 
may be forced out as larval food. Snodgrass has shown 
that this cannot happen without tearing the muscles of the 
1 In Winterstein's Handbuch der vergleichenden Physiologie, vol. 2, 
Heft I. 
1 Petersen, Hans, 1912. Beitrage zur vergleichenden Physiologie der 
Verdauung. V. Die Verdauung der Honigbiene. Pflilgers’ Arch, fur die 
gesammte Phys. d. Menschen u. d. Tiere, XLV, pp. 121-151. 
