"STRAINS" IN HVDATINA SHNTA. 215 



form evidence that these two races were potentially alike in their 

 power to produce male-producing females but when conditions 

 were unfavorable they differed, as shown in the parallel series, in 

 their re-p. ,ii-iveiiess to the influences that so acted upon the 

 females as to cau-e them to produce male-producing daughter 

 fem. ili--. Ho\ve\er. when race C was put into newly made un- 



ked culture media in battery jars very few fenili/ed eggs 

 were prodm ed, thus K-eming to show either that thi- race C was 

 potentially different from the other two races in it- rapacity t 

 produce male-producing females or that it was not as ea-ily acted 

 upon by iln- male-producing female influences as were races .1 

 and /v \oi\\hh-tanding this fact that race C produced very 

 le\\ male- producing f. -males when put into battery jar- containing 

 dilute iiiiiooki-d horse manure media it should be stated that in 

 the e.irK lii.~tor\ of race C' it had as high a percentage of male- 

 producin- female- in the first four generations as \\a- found in 

 either race .1 or B. Table- II. The race was isolated from a 



. r.il cnli ure jar in \\hich an abundance of males were appearing 

 at the time i >l i-o|ation. Beginning with generation ii\e verj 

 le\\ in. ile- appeared thereafter. This early history sh.\\ - that 

 race Cat one time was as potential in its power to produce male- 

 producipv: it-males as races A and B, but whether it later lost 

 thi- power ( -r never was again subjected to as favorable intlnem es 

 for the production of male-producing females it i- impo--ib!e 

 to state. \\ ii.ii> \<r may be the true explanation of thi- di\-r- 

 gence in the male-pnKlucing female rates of the three races it 

 -iiteK indicate- a dillerence in the races either in their capacity 

 to product- male-producing females or their responsiveness to 

 tin- inlluenct - thai cause male-producing femak-- to U- produ. .-d. 

 I'niinett coinliidid that he found "sex -train- ' in Ilydntiiid 

 / \\hich differed in their power to prodnc.- male- and even 

 i on.-ludt-il that he found some strains that produced no male-. 

 It is verj po--ible that such maleless strain- \\ire n-alh like 

 rat c ' in the above experiments. From ob-<-r\ atioiis and experi- 

 ments publi-hed in an earlier paper ('07 . it was -lu>\vn that no 

 pun- female -trains could be found. The re-ult- of the pie-.nt 

 experiment- o>i roborate this earlier conclusion. However, the 

 evidence at that time showed no strains of anv kind but the 



