IOO P. W. WHITING AND ANNA R. WHITING. 



brother produced males type 3, reduced I, ivory 3, and females 

 type 8, reduced 6, ivory 7, ivory reduced 4. As far as may 

 be judged from these small numbers, this female did not differ 

 in her breeding behavior from her type sisters. The reduced 

 right primary wing may be explained by some local mitotic 

 irregularity involving a single chromosome or a reduction of the 

 whole complex. In the latter case freak 279 may be regarded as 

 a gynandromorph. 



GYNANDROMORPHS. 



As a tentative explanation of the origin of gynandromorphs 

 or sex mosaics in Habrobracon it is suggested that they may be 

 formed in a manner similar to the mosaic males above discussed, 

 except that one of the ootids is fertilized. There are then two 

 cleavage nuclei, a haploid of maternal origin and a diploid of 

 bisexual origin. 



Sex of the various body regions of gynandromorphs is to be 

 recognized by comparison with certain differences between normal 

 males and females. Eyes show no obvious sex difference but 

 sex of the head may be identified in almost all cases by number 

 of joints in antennae. The long antennae of the male stand in 

 contrast to the short antennas of the female. In counts of 

 joints in 2,407 "normal" male antennae the modal number was 

 twenty-three. A single antenna contained twenty-five while 

 three had only eighteen. In counts of joints in 1,821 "normal" 

 female antennae the modal number was fifteen; none had over 

 sixteen while four had as low as eleven. Deviation in "normal" 

 individuals is therefore much greater in the minus than in the 

 plus direction. No aberrancies have occurred increasing the 

 number of joints but "deficiency" (Whiting, P. W., 19266) 

 reduces number in either sex. In the latter case ante^nal 

 joints tend to be fused or tapering. Shortening therefore indi- 

 cates antennae as female only if joints are of normal form. 



Primary wings of the female average slightly larger than of 

 the male. Variation within each sex is so great that no reliance 

 may be placed on this character. Obvious asymmetry in wing 

 size may, however, be suspected to indicate sex difference between 

 left and right sides of the same gynandromorph. 



