264 



The Journal of Heredity 



FEMALE WASPS WITH ABNORMAL ANTENNAE 

 Non-genetic abnormalities of antennae include branching and asymmetrical shortening or 

 omission. The females in the above photographs show also genetic defects of venation — the vein 

 r4 (see wing o in Fig. 1) (about xll) (Fig. 22.) 



show much variability in number of 

 defectives as well as in the extent of 

 defect in those affected. One stock, 

 called type, has produced only one 

 defective in several thousand individ- 

 uals. This wasp had one wing normal 

 while the other lacked r4 altogether. It 

 bred like the rest of the type stock and 

 hence the defect was purely somatic. 

 Other stocks regularly produce one or 

 two defectives in three or four hundred 

 individuals, while still others have 

 about ninety percent defective, the 

 mode appearing in the class lacking ri in 

 both wings, completely or almost com- 

 pletely. Crosses of type with high 

 grade defective stock illustrate sex- 

 linkoid inheritance, the males resemb- 

 ling the maternal strain while the 

 heterozygous females are for the most 

 part normal showing, however, varia- 

 tion to dcfccti\'eness of intermediate 

 grade. These females when isolated 

 produce normal and defective males in 

 numbers almost equal, there being a 

 slight excess of normals, corresponding 

 to the somatically normal in defective 

 stock. It is clear that the high grade 

 defective stock differs from type by one 

 Mendelian factor affecting the wings. 



ORANGE MUTATION 



In a single individual appearing 

 among the 254 male offspring of a 

 virgin female the eyes, both compoimd 



and simple, were orange instead of the 

 typical black. This male was crossed 

 to various black-eyed females and 

 black-eyed sons and daughters re- 

 sulted. When these were mated to- 

 gether, they produced black and orange 

 males in equal numbers, but all the 

 daughters were black and indistin- 

 guishable from black stock. The 

 failure of orange to appear among the 

 daughters of black-eyed fathers, shows 

 that the males are not heterozygous, 

 but haploid. In other words, all the 

 spermatozoa produced by any one 

 male are alike. Since black is dominant 

 and all females result from fertilized 

 eggs, all the daughters of any black- 

 eyed male must be black. The orange 

 mutant was crossed to a few of his 

 heterozygous daughters. Orange and 

 black females as well as males were 

 produced as expected. Heterozygous 

 females isolated as virgin have given 

 black and orange males in equal num- 

 bers. Orange females isolated as virgin 

 produce only orange males and orange 

 stock breeds true. 



When orange females are crossed to 

 black males all daughters are black 

 and l^reed like noriual hetcrozygotes 

 according to expectation. The sons for 

 the most part are orange arising pre- 

 sumably from unfertilized eggs. A few 

 however are regularly black deriving 

 their eye color from the sperm and 



