80 " Gyaandromorplilsiii " and Kindred Problems 



III. Secondary Somatic Hermaphrodites. 



Sex gland ur (jlands of one sex only ; secondary sexual apparatus of one 

 sex only, that corresponding to the sex gland present. Secondary 

 sexual characters of hath sexes present in antennae, wings, or other 

 parts of body. 



(a) Male type, with one or two testes. 

 (6) Female type, with one or two ovaries. 



The majority of gynandromorphous insects fall into Group II, 

 primary somatic hermaphrodites, relatively few into Groups I and III. 



Of genetic hermaphrodites the only examples which can be included 

 in the bilateral group are the Lymantrias bred by Goldschniidt and 

 others, which had ovarian and testicular tissue mingled in the follicles 

 of both gonads (Zwitter-driise). 



In the unilateral group is a sp)ecimen of Polyergus rufescens Latr. 

 described by Wheeler and an Amorpha populi figured by Wenke. The 

 latter had two ovaries, one very rudimentary ; but their oviducts opened 

 into vesiculae seminales, and below this the ducts each gave rise to a 

 glandula accessoria and then ended blindly. Attached to the side of 

 one ovary there was a testis containing no spermatozoa. To explain 

 the existence of genital organs arranged in this mosaic manner, we must 

 suppose that a mosaic arrangement of cells occurred in the germinal 

 epithelium and primitive genital tract. The germinal epithelium of 

 one side must have consisted of cells wholly female in character and so 

 gave rise to an ovary : that of the other side must have been divided 

 longitudinally into a part consisting of cells of female character and a 

 j)art consisting of cells of male character. The former gave rise to 

 a rudimentary ovary and the latter to a rudimentary testis. 



An irregular mosaic arrangement of the embryonic tissue of the 

 lower part of the genital tract gave rise to the irregular mosaic arrange- 

 ment of male and female sexual organs. 



Such a mosaic arrangement of embryonic tissue giving rise to the 

 wings and other parbs of the body almost certainly occurs, and there 

 seems to be no reason why a similar arrangement should not occasionally 

 occur in that from which the gonads and other parts of the sexual 

 apparatus arise. 



The great majority of genetic hermaphrodites in insects fall into 

 the lateral group. The gynandromorphous birds are also lateral genetic 

 hermaphrodites and are all alike in having a testis on the male side 

 and an ovary on the female. 



