GYNANDROMORPHS AND OTHER IRREGULAR 

 TYPES IN HABROBRACON. 



P. W. WHITING AND ANNA R. WHITING, 

 UNIVERSITY OF MAINE. 



In a series of papers and abstracts on the genetics of the 

 parasitic wasp, Habrobracon, mention has been made of various 

 irregular types not falling in line with the general principle of 

 sex-linkoid inheritance. 



These cases are considered to be of fundamental significance 

 from the point of view of maturation and cleavage. They include 

 impaternate females, mosaic males and females, gynandromorphs, 

 and intersexual males. 



Among the higher Hymenoptera it is now generally assumed 

 that females arise from fertilized eggs, males from unfertilized. 

 Exceptions to this have, however, been claimed in certain ants 

 (Wheeler, W. M., 1903). Among the lower Hymenoptera con- 

 ditions are much more irregular. Some species of saw-flies are 

 exclusively or predominantly "female-producing," thelytokous; 

 others "male-producing," arrenotokous; while others, amphi- 

 tokous, produce both sexes parthenogenetically. 



Gall wasps with their alternation of sexual and parthenogenetic 

 generations have in the latter both male-producing and female- 

 producing females. 



Polyembryonic Chalcidoids produce male broods from un- 

 fertilized eggs, female broods from fertilized, but Patterson 

 (Patterson, J. F., 1917) has shown that certain broods, pre- 

 dominantly female, may contain a few males, presumably derived 

 from mitotic irregularities in the polygerm. 



Among the Ichneumonoids, to which group Habrobracon 

 belongs, arrenotoky is the rule but some species are thelytokous. 

 In a species that is predominantly arrenotokous it has been 

 shown (Hunter, S. J., 1909, and Webster, F. M., 1909) that the 

 tendency to produce females is probably inherited. 



The irregular forms discussed in the present paper have 



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