332 BAKER : HYDROPIUS FUSCIPES. 
are also supplied from the head to the cesophagus. The three 
thoracic ganglions are globular in shape and send off nerves to the 
legs as well as the segments. The abdominal ganglions, which are 
seven in number, are oval, with the exception of the last one. 
Nerves are supplied from each of these ganglia to the segment in 
which it is placed. All these ganglia are united to each other by 
a double cord. In the perfect insect the abdominal ganglia coalesce, 
and the optic nerves are not separate but form one nerve trunk to 
each of the two compound eyes; in other respects the structure of 
the nervous system is the same in larva and imago. 
he alimentary canal (Fig. 7) consists of little 
more than a long tube running the whole length 
of the animal, and consisting of three divisions— 
the cesophagus, the stomach with its Malpighian 
tubules attached at each end, and a_ short 
intestine. 
The circulatory system can be seen very 
plainly in a young larva. It consists of a long 
vessel, constricted at each segment, which pumps 
the circulatory fluid forward ee the body, 
bathing all the organs. 
When the larva is ready to pupate it crawls up 
of an inch below the surface (Fig. 8) but connected 
with the air by a small aperture. Here it remains 
for from three to six days and then turns into 
the pupa. e pupa is perfectly white and 
exhibits all the parts of the perfect insect in the 
usual shrouded form (Fig 9). Very long spines 
project from the prothorax, and the whole body of 
the pupa on the dorsal side is covered with spines 
Fig. 7. 
Alimentary canal. 6. 
——— : 
Fig. 8. Pupa in situ. x2. Naturalist, 
