THE STICK INSECT. 83 
delicate pedunculated, pyriform vesicle, the sperma- 
theca. There are no glandular appendages. In the 
male the testes are a grape-like mass of follicles 
round a dilated portion of the vas deferens. The 
vasa deferentia unite to forma ductus eyaculatorius, 
on which there are no glandular appendages. 
7. Nervous system. Hold the head firmly with a bent 
needle, and slice off the upper portion with a scalpel, 
cutting from before backward; enlarge the opening 
with scissors if necessary. The muscles cf the head 
will be exposed. Separate them along the median 
line, and below will be seen the oval cerebral gang- 
lion. From this proceeds anteriorly a pair of nerves 
to the antennz, and laterally a pair to the eyes. 
Two nerve cords come off from behind which pass on 
each side of the pharynx, and meet behind it in the 
first thoracic ganglion. The two cords continue 
through the whole of the thorax and abdomen, with 
three ganglia in the thorax and seven in the abdo- 
men. Cut out a portion of the abdominal nerve 
cords, and examine with the microscope ; lateral 
nerves are given off from the ganglia, but not from 
the cords. There is also a visceral or stomato-gastric 
nerve system which arises from the anterior border 
of the cerebral ganglion and goes to the pharynx, 
and then passes backward on the cesophagus; this 
nerve, the nervus recurrens, is connected with ganglia 
on the cesophagus behind the cerebral ganglion 
This part of the nervous system is difficult to make 
out. 
8, Examine with the quarter objective a portion of the 
muscles from the head. They are striated. Notice 
the trachez traversing them. Clear away the fatty 
