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407-422, PI. XXII, 1907. P g 



EXPERIMENTAL ZOOLOGY 

 The Effects of Extirpation and of Transplantation of the Reproduc- 

 tive Organs in Insects — Meisenheimer 1 has carried on extensive 

 experiments with moths for the purpose of determining whether 

 the differentiation of the accessory genital organs and of secon- 

 dary sexual characters is dependent on the ovary and testis or 

 whether their development is independent of the sex glands. The 

 material used was chiefly the moth Lymantria (Oeneria) rfispar 

 L., which lias a marked sexual dimorphism and recovers well from 

 the effects of operation. The caterpillar passes ihrough five moults 

 hefore pupation, the first moult taking place about five days after 

 hatching, and each later one in from eight to twelve days, accord- 

 ing to temperature; pupal ion takes place in about six days after 

 the last moult and lasts for three or four weeks. The operations 

 consisted of removal of sex glands, removal of anlage of accessory 

 genital apparatus, transplantation of sex gland of the opposite 

 sex, and removal of wing anlage. The operations were done on 

 all six caterpillar stages, the extirpation of sex glands being done 

 by means of an electric needle in the first two stages, and by a 

 knife in later stages. The mortality was very great, only 51 

 caterpillars surviving the electrical operation out of 1,250, and 

 176 out of 537 surviving when the organ was cut out. 



In moths from caterpillars whose testes had been removed, the 

 vasa deferentia ended blindly: othei-wi.se the accessory sexual 

 apparatus was perfectly normal. In one ease, the vasa defer- 

 entia had fused at their free ends, owing to their proximity at 

 the time of healing. The secondary sexual characters, such as 

 the size, coloring and markings of the wings, were of the normal 

 male type. When, in addition to castration, the anlage of the 

 accessory sexual organs, including the vesicuhr seminales, ductus 



and Geschlechts-Differenzierung. ' ' 



