170 HA-RRY FEDERLEY 



SUMMARY. 



Non-conjugation of the chromosomes in the gametogenesis of spe- 

 cies hybrids results in partial or total sterility in Fi, and non-segregation 

 in F2 and in back-crosses. 



In the species hybrid Chaerocampa porcellus Ç X Ch. clpenor cT all 

 the 29 porce//us-chromosomes conjugate with the 29 e/penor-chromo- 

 somes both in the spermatogenesis and in the oogenesis. In this case fer- 

 tility in Fl and segregation in Fo and in back-crosses is consequently to 

 be expected. 



Fl must also in its character of species hybrid be considered as ex- 

 tremely fertile. 



The horn of the new-hatched larva of elpenor is very long and 

 dark, that of porcellus is a raised wart. Fi is very like elpenor. 

 The 5 F-i-individuals also possessed a long horn as Fi. The 38 larvae 

 of a back-cross porcellus^ XFiçfhave all a porcellus-\ike small cone. 

 Consequently segregation had not taken place as to this character. 



The experiments will be continued. 



ZITIERTE LITERATUR. 



1. Federley, Harry. 1916. Chromosomenstudien an Mischlingen. III. Die Sper- 



matogenese des Bastards Chaerocampa porcellus Ç X elpenor cf- Öfversigt af 

 Finska Vetenskaps-Societetens Förhandlingar. Bd. 53 A, N:o 12, 17 S. 



2. Hartmann, Max. 1918. Theoretisclie Bedeutung und Terminologie der Verer- 



bungserscheinungen bei liaploiden Organismen. Zeitschr. ind. Abst.- und 

 Vererbgslehre. Bd. 20. S. 1—26. 



3. Whiting, P. W. 1918. Se.\-Determination and Biology of a Parasitic wasp, //arf- 



robracon Brevicornis (VVesmael). Biol. Bull. Vol. 34, p. 250—256. 



4. — 1921 a. Studies on the Parasitic wasp, Hadrobracon Brevicornis (Wesmael). 



I. Genetics of an Orange-eyed Mutation and the Production of Mosaic from 

 Fertilized Eggs. Ibid. Vol. 41, p. 42 — 54. 

 — 1921 b. II. A Lethal Factor Linked with Orange. Ibid. Vol. 41, p. 153—155. 



