QO P. W. WHITING AND ANNA R. WHITING. 



occurred in Habrobracon juglandis (Ashmead) with the exception 

 of gynandromorphs, freaks 269 and 271, and intersexual males, 

 freaks 193, 273, 274, and 275. The latter were found in the 

 European species, Habrobracon brevicornis (Wesmael). 



IMPATERNATE FEMALES. 



In the stock of Habrobracon juglandis (Ashmead) from Lan- 

 caster, Pennsylvania, females have been, with one very doubtful 

 exception, derived from mated females. In material from Iowa 

 City and in descendents of crosses between the Lancaster (L.) 

 and Iowa City (I.) materials, undoubted cases of thelytoky have 

 occurred. 



Females are exposed to males either in culture vial a or 

 previously after which they are ordinarily separated. The 

 females are then passed through vials b, c, etc. Relatively 

 more daughters are produced in the earlier vials. The supply of 

 sperm seems to be exhausted after a length of time varying in 

 individual cases. When female ratios per brood are extremely 

 low the few females usually occur in vial a. This applies for 

 example to the daughters of patroclinous diploid males. Single 

 females occurring in later vials may, therefore, be suspected of 

 being impaternate unless other conditions preclude the possibility. 



In individual culture counts of the pure I. material, thirty- 

 seven virgin females produced only males, 3,288. Thirty-one 

 females that had been exposed to males produced only males, 

 3,746. Sixty-three females exposed to males produced both 

 males, 2,933, and females, 2,719. Female percentages in these 

 sixty-three cultures ranged from 18 to 74. 



Besides the bisexual broods above recorded there were some 

 in which but a single female appeared. 



In one case (April, 1923) a female which was observed to 

 mate with a single male produced 142 males and in vial c a 

 single female. 



In another case (April, 1923) a female which had been exposed 

 to males produced 97 males and in vial e a single female. Each 

 of these two cases is aberrant in that only one female appeared 

 and she was produced relatively late in the mother's life. They 

 are, however, inconclusive as regards thelytoky since the mothers 

 had been exposed to males. 



