282 'Journal of Comparative Neurology and Psychology. 



ovipositor is brought into contact with the surface upon which 

 the insect rests. This serves as a stimulus for the action of the 

 lips. Unfortunately, no experiments were tried to determine 

 whether the nature of the material affected the functioning of these 

 lips. It would be interesting to know whether the lips would 

 open if these sensory hairs came in contact, for instance, with 

 another egg. If not, we could understand how it was that one 

 egg is rarely placed, either under normal or experimental condi- 

 tion, upon another. A study of the action of the ovipositor in this 

 regard might also throw light upon the "selections" of various 

 insects of certain plants only for placing their eggs — these plants 

 being the particular food to which the larvae of their kind is adapted. 



Series 15 was a further reduction of the nervous system. 



The first abdominal ganglion lies in the second abdominal seg- 

 ment. The commissure connecting it with the second abdominal 

 ganglion lies close to the ventral surface of the body. This com- 

 missure can be snipped in two through the ventral wall of the 

 body with but little loss of blood. With the first abdominal gan- 

 glion severed from the rest of the nervous system, egg placing fol- 

 lowed, as before, upon stimulation, the rate of egg placing not 

 being materially lowered. By snipping through the suture sepa- 

 rating the third and fourth abdominal segments, the second 

 abdominal ganglion was severed from the posterior part of the 

 nervous system. Again stimulation resulted in egg placing. 

 Snipping through the suture separating fourth and fifth abdomi- 

 nal segments severed the third abdominal ganglion from the fourth 

 and last abdominal ganglion. As before, egg-placing took place 

 with no more hesitancy than in the intact nervous system. That 

 severance of the commissures in insects thus operated upon had 

 actually taken place was later verified in several cases by dis- 

 sections. 



Upon severance of the nerve connections between the last abdom- 

 inal ganglion and the ovipositing apparatus, stimulation failed to 

 bring about movements in the ovipositor. That this was not due 

 to loss of blood or disturbance of the respiratory apparatus incident 

 upon the incisions, is evidenced by the fact that the ovipositing 

 apparatus (egg tubes, ovipositor, etc.) with its controlling ganglion 

 may be completely severed from the body, and eggs will yet pass 

 down through the egg tube and out between the lips of the ovipos- 

 itor, if the parts are kept normally moist. 



