266 'Journal of Comparative Neurology and Psychology. 



cles and skin of the fifth abdominal segment. Nerves 5 and ^ to 

 the muscle and skin of the sixth abdominal segment. Nerves 5, 6 

 and 7 to the reproductive organs and muscles of the last abdominal 

 segment. A certain neurone of the fourth nerve ends in the v^alls 

 of the oviduct. Neurones of the fifth and sixth nerves end in the 

 muscles controlling the anal opening and ovipositor, extensors and 

 retractors, and opening of the bursa. Neurones of the seventh 

 nerve are distributed to the ovipositor, to the w^alls of the colleterial 

 gland, to the vagina and to the rectum. 



The silkw^orm takes no food in the adult stage, although living 

 from ten to tw^enty days in a strong, vigorous condition. The 

 female moves about but little. The mating instinct, to the end of 

 egg fertilization and preservation of the species, is the only con- 

 spicuous adult instinct exhibited. The reflexes connected with 

 reproduction are the only apparent spontaneous reflexes exhib- 

 ited. No difficulties are encountered in experimenting with these 

 insects in the way of disturbing influences from fright, hunger or 

 efforts to get away. 



While not attempting in this series of experiments to cover com- 

 pletely the ground of the functioning and nervous control of the 

 reproductive system, much interesting data was obtained relative 

 to its behavior. 



NORMAL BEHAVIOR. 



Adults leave the cocoon under normal conditions between 7 and 

 8 a. m. The female at once extends the alluring glands. If a 

 male is near, mating takes place at once. The mated pair remain 

 almost continuously in copula from twenty-four to thirty-six hours, 

 after which, for the next twelve to seventy-two hours there are 

 intermittent periods of egg laying. Within two to five days after 

 issuing, one to three days after mating, a female will have ovi- 

 posited her full quota of eggs. There is no regularity with refer- 

 ence to total number of eggs oviposited by individuals. These 

 range in normal healthy individuals from three hundred to con- 

 siderably over five hundred eggs in the races used for this work. 



In the unmated insect, as in the mated, there is no regularity as 

 to the number of eggs oviposited, but eventually the full quota of 

 eggs are placed. 



