THE PARASITIC WASP, HADROBRACOX BREVICORNIS. 53 



dromorph bees, but Boveri (1915) contended that the male 

 parts were of maternal color and held that a single sperm nucleus 

 had fused with one of the products of parthenogenetic cleavage. 

 Morgan's hypothesis apparently fits the von Engelhardt bees 

 (1914) in which the male parts resembled the father. Cleavage 

 of a single sperm nucleus, however, might be followed by subse- 

 quent fusion of one of the products with the female pronucleus 

 and a result would be obtained similar to Morgan's hypothesis 

 of polyspermy. It is also obvious that haploid nuclei might be 

 derived from both parents and the resulting male parts would 

 then be of mixed origin. 



Doncaster (1914) has demonstrated the existence of binu- 

 cleated eggs in Abraxas; and it has been suggested that if one of 

 these contained the sex-chromosome and the other lacked it, 

 their simultaneous fusion with two sperm nuclei would result in 

 a gynandromorph. 



Morgan and Bridges (1914) have shown that in Drosophila 

 gynandromorphs and other mosaics result from dislocation of 

 a sex-chromosome during cleavage or embryonic development. 

 The male parts are here of course diploid for autosomal factors. 



Mosaics due to somatic mutation have likewise been reported 

 in several plants and animals. 



It is to be noted that the mosaic males reported in the present 

 paper result from the cross of orange female by black male. 

 The reciprocal cross has failed to give any anomalous results. 

 Whether the production of anomalous males is necessarily cor- 

 related with the fact that orange comes in from the motner, 

 black from the father; or whether black females may be obtained 

 which will give anomalous results when crossed to orange males, 

 is uncertain. In the former case the orange factorial difference 

 would itself be responsible for the production of anomalous 

 males. In the latter case the production of irregularities would 

 perhaps depend upon a factorial difference other than that of 

 orange. The answers to this question and to others raised in the 

 present paper may be given by investigations now in progress. 



