114 " Gynandromorphisin " and Kindred Problems 



Hybrid Gynandromokphs. 



Gynandromorphism is far commoner amongst hybrids than amongst 

 pure races of Lepidoptera. 



The well-known hybrid hawk-moth, Amorphu (Smerinthus) hybr. 

 hyhridus Steph. {A. ocellatus ^ x A. populi % ) and Amorpha hybr. 

 operosa Stand fuss (A. ocellatus (f x A. populi var. uustati ^ ), gives 

 males with a few gynandromorphs and no females. The gynandro- 

 morphs as a rule resemble females and are quite symmetrical. The 

 internal organs according to Roepke are similar in both hybrids. Two 

 ovai-ies are present much distorted and atrophic. The other internal 

 sex organs were in part hypertrophied, in part atrophied, and in some 

 portions were completely cut off from the rest. No male internal 

 organs were present. Excellent figures are given by Roepke. 



In the external genitalia there was a curious mosaic of male and 

 female parts, male portions preponderating in some, female in others, 

 with every degree of intermediate arrangement. 



One hybrid operosa had a partially bifid uncus with two small 

 patches of ovipositor inlaid upon one side and one patch upon the 

 other. Burrows and Pierce find a similar arrangement in the numerous 

 examples of hybrid hybridus they have examined, and I possess one 

 showing the same features. Though a series could be prepared to show 

 a transition from a preponderantly female to a preponderantly male 

 type, in all cases the genitalia are very nearly symmetrical and therefore 

 quite unlike most natural gynandromorphs. In some of these quite 

 small islands of thick male chitin are found let into larger areas of 

 thinner female chitin. 



One inale gynandromorph of hybr. hyhridus was found by Roepke. 

 It possessed two testes with normal male accessory structures and male 

 external genitalia with the exception of two large areas of ovipositor 

 replacing part of the undivided uncus. Males of these hybrids have 

 testes, of normal or reduced size, but with no fully formed spermatozoa. 

 The inner and outer genitalia are those of normal males. 



Halved gynaudromorphous examples of hybr. hyhridus have been 

 recorded by Birchall, Briggs, Schultz and Newman, but though the 

 sexual characters are completely segregated, both halves show an equal 

 admixture of the somatic characters of both parents. Such completely 



