184 
Psyche 
[September 
Destruction of the fifth abdominal ganglion of another in- 
sect resulted in a temporary cessation of respiratory movements. 
In the case of a larva with the seventh abdominal or ter- 
minal ganglion destroyed the effects were more marked. Not 
only were the respiratory movements much altered, but the 
movements of the cloacal spines were completely inhibited. 
The last two abdominal ganglia were successively destroyed, 
and later the entire abdominal part of the nerve cord was re- 
moved. Immediately after the destruction of each single gang- 
lion there was a suspension of respiratory action. Later these 
movements became normal. The removal of all abdominal 
ganglia led to a complete and permanent cessation of all res- 
piratory movements. There was also a marked decrease in 
volition, and no responses to visual stimuli. 
The suboesophageal ganglion of a larva was destroyed. This 
inhibited the movements of the mouth-parts; otherwise the 
insect was normal. 
In another case the brain of a larva was cut through in a 
median plane. The larva tilted its body to the right, and crawled 
and swam in circles in the same direction. Its reflexes were 
quite normal. 
When the brains of several larvae were removed through 
large holes in the heads, and the openings closed with asphaltum, 
a strong shock effect was produced. After that, responses were 
normal. The breathing, at first irregular and spasmodic, soon 
became normal. When resting on a solid surface out of water; 
the larvae responded by movements of the abdomen or by crawl- 
ing. The mouth-parts, and the legs, exclusive of coordinated 
actions such as crawling, moved spontaneously. Swimming 
movements were not strong, and probably resulted simply from 
normal respiratory movements. There was no volition and no 
response to visual stimuli. 
The results of Baldus (1924) with Aeschna cyanea seem to 
have been similar to those just described. Baldus states that he 
was able to keep larvae alive for long period with no heads at all. 
Most of my specimens did not live over forty-eight hours. But 
my results agree very well with those of Baldus: namely that 
the brain of the larva, while important, is not as essential to the 
