J. W. H. Harrison 37 



size or to reach the exterior owing to the overpowering femaleness 

 of the insect. 



[I have to acknowledge the receipt of a grant from the Government 

 Grant Committee of the Royal Society in aid of the above investigation.] 



EXPLANATION OF PLATE \. 



1, 2, 3, 4, 5, 6. Intersexes of pilzii ( = pomonaria $ x hirtaria (?) ? x pomonaria (? . 



7, 8. Intersexes of lapponaria $ x pomonaria ^ . 



9. Male hirtaria. 10. Female hirtaria. 11. Male pomonaria. 



12. Female pomonaria. 13. Male pilzii. 14. Female pilzii. 



LITERATURE QUOTED. 



Brake. "Resultate der Kreuzung zwischen Lymantriajaponica Motsch. und Lyman- 



tria dispar." Entonx. Zeitschrift, 1907. 

 Brake and Fbings. " Einige weitere Ergebnisse der Brakeschen Lymantria dispar 



L. Zuchten." Entom. Zeitschrift, 1911. 

 Chapman. " An Experiment on the Development of the Male Appendages in Lepi- 



doptera." Transactions of the Entomological Society of London, October 4, 1912. 

 Bridges. " Non-disjunction as a Proof of the Chromosome Theory of Heredity." 



Genetics, Vol. i. pp. 1—52, 107 — 163. Princeton, January — March, 1916. 

 CoRRENS. " Die Rolle der mannlichen Keimzellen bei der Geschlechtsbestimmung 



der gyndiozischen Blutenpflanzen." Ber. deutsch. Bot. Ges. 26a, 1908. 

 Doncaster. " On the relation between chromosomes, sex-limited transmission, and 



sex determination in Abraxas grossulariata." Journ. of Genetics, iv. No. 1, 1914. 



The Determinaiion of Sex. Cambridge Univ. Press, 1914. 



GOLDSCHMIDT. " Erblichkeitstudien an Schmetterlinge, I." Zeitschrift fUr induct. 



Ahstammungs- und Vererbungslehre, 7, 1912. 



and Poppelbaum. Idem. ii. Ibid. 11, 1914. 



Harrison. "The Hybrid Bistoninae." Etudes de Lepidopterologie comparee. 

 Fasc. VII. Rennes, 1913. 



" Studies in the Hybrid Bistoninae." Journ. of Genetics, Vol. vi. No. 2, 1916. 



"The Geographical Distribution of the Moths of the Geome+rid Subfamily 



Bistoninae." Naturalist, 1916, 1917. 



" Studies in the Hybrid Bistoninae, II." Journ. of Genetics, Vol. vi. No. 4, 



July 1917. 



" Genetical Studies in the Moths of the Greometrid Genus Oporabia." Journ. 



of Genetics, Vol. ix. (In the Press.) 

 Hertwig. "tjber den derzeitigen Stand des Sexualitats-problems." Biolog. Zen- 



tralbl. p. 1, 1912. 



