APPENDIX 85 



Influence of the Primary Reproductive Organs on the Secondary Sexual 

 Characters, in Jour. Exper. Zool., v. 1, pp 601-605, Dec., 1904. 



In this paper is recorded an account of the process of extirpating the 

 developing ovaries and testes of various silkworm individuals in various larval 

 stages. These individuals after pupation and issuance as adults were then 

 examined to note if any change or lack of normal development had taken place 

 in those structures showing secondary sexual differences, particularly the 

 antennae. 



The extirpation of the developing reproductive organs, which lie just beneath 

 the dorsal wall in the fifth abdominal segment, was accomplished by searing with 

 a hot needle. The slight wounds soon closed, and most of the larvae were reared 

 to moths. In all cases the moths were dissected to be sure that the destroying 

 of the ovaries or testes had been complete and to see whether any regeneration 

 of these parts had taken place. No such regeneration occurred, and in a score 

 of moths the ovary or testis of one or both sides was found to be wholly wanting. 



There was no case of the absence or modification of the secondary sexual 

 characters in any of the moths. All males had both antennae of the usual male 

 type, although the testis of one side or the other, or of both sides, was wholly 

 wanting. 



Some Silkworm Moth Reflexes, in Biol. Bull., v. 12, pp 152-154, Feb., 

 1907. 



Silkworm moths, Bombyx tnori, are sexually mature and eager to mate im- 

 mediately on issuing from the pupal cocoon. They take no food (their mouth 

 parts are atrophied), they do not fly, they are unresponsive to light; their whole 

 behavior, in fact, is determined by their response to the mating and egg-laying 

 instincts. We have thus an animal of considerable complexity of organization, 

 belonging to a group of organisms well advanced in the animal scale, in a most 

 simple state for experimentation. 



The female moth, nearly immobile, protrudes a paired scent-organ from 

 the hindmost abdominal segment, and the male, walking nervously about and 

 fluttering its useless wings, soon finds the female by virtue of its chemotactic 

 response to the emanating odor. Males find the females exclusively by this 

 response, but orient themselves for copulation (after reaching the female) by 

 contact. When two males accidentally come into contact in their moving about 

 they try persistently to copulate. 



A male with antennae intact, but with eyes blackened, finds females imme- 

 diately and with just as much precision as those with eyes unblackened. A male 

 with antennae off and eyes unblackened does not find females unless by accident 

 in its aimless moving about. But if a male with antennae off does come into 

 contact, by chance, with a female it always (or nearly so) readily and immedi- 

 ately mates. The male is not excited before touching the female, but is imme- 

 diately and strongly so after coming in contact with her. Males with antennae 

 on become strongly excited when a female is brought within several inches 

 of them. 



The protruded scent-glands of the female are withdrawn into the body 

 immediately on her being touched by a male. If the scent-glands are cut off and 

 put wholly apart from the female, males are as strongly attracted to these 



