GYNANDROMORPHS IN IIABROBRACON. QI 



Two cases of undoubted thelytoky occurred in the pure I. 

 material. In one (December, 1922) a virgin female produced 97 

 males and in vial b a single female, freak 277. In the other 

 (April, 1923) a virgin female produced 97 males and in vial c a 

 single female, freak 278. 



Freak 276. A sooty (mesosternum) female from I. stock 11 

 (OD n s n ) was mated to an orange (eye), defective (vein r 4 ) 

 male, od II95 S n , derived from L. stocks 6 and 10 and I. stock u. 

 There were produced males type i, sooty 49, and females- 

 type 87, grading to sooty 8, and defective i. One of these type 

 females produced males type 7, sooty 29, defective 29, sooty 

 defective 4, orange 4, orange sooty 29, orange defective 28, and 

 orange sooty defective 13, showing free segregation of orange 

 and linkage of sooty and defective. In vial/ an orange female, 

 freak 276, was found (April, 1923). No males appeared. Since 

 the FI female had been exposed only to her black-eyed brothers 

 her single orange daughter must have been impaternate. She 

 produced males orange i, orange sooty 7, orange defective 5, 

 orange defective sooty 8, and females orange 3, orange sooty 3, 

 orange defective 5. These numbers are not very satisfactory 

 for such variable characters as sooty and defective. Moreover, 

 L. and I. stocks possess minor factors which, when recombined, 

 produce the characters sooty and defective without the factors 

 s n and d II95 . 



It is assumed that thelytoky occurs by the suppression of 

 the second oocyte division. In this case the first division 

 separated the tetrad into dyad OO which passed into the polar 

 body, and oo which entered the cleavage nucleus. 



Origin of Freaks 250, etc. An orange, defective, wrinkled male 

 of the twelfth inbred generation descended from the impaternate 

 female, freak 276, was crossed with a sooty female from I. stock 

 n. There resulted in FI 34 black males and 120 black females. 

 Twenty-three of these females were isolated. Fifteen of them 

 had evidently mated with their black-eyed brothers since they 

 produced black-eyed females. 



The F 2 generation consisted of males type 217, sooty 240, 

 defective 91, defective sooty 91, wrinkled and wrinkled defective 

 378, wrinkled sooty and wrinkled sooty defective 123, orange 193, 



