332 Dr. Cockayne on Gynandromorphous Lepidoptera. 



hybrid gynandromorphs, and, thirdly, the heterochroic 

 gynandromorphs of Hemeropkila, bred by Simmons. 



There is no actual proof that they ever arise in the way 

 Boveri or Morgan in 1905 and Harrison in 1916 suggested, 

 but, on the other hand, there is no proof to the contrary. 



The condition in the Eugster gynandromorph bees, 

 which is the chief support of Boveri, is no longer such 

 valuable evidence in the light of the opposite condition 

 met with in von Engelhardt's. Toyama's Bombyx mori 

 and Harrison's hybrid Ennomos may be explained on Mor- 

 gan's first theory. But the condition in all these insects 

 can be explained by his second theory, the one theory 

 which has received definite proof, and it is more probable 

 that all arise in one way than that they arise in three 

 different ways. 



Bibliography. 



Baker, Bethune, G. Trans. Ent. Soc. 1891, pp. 1-6. 



Birchall. Entomologist, 1881, XIV, p. 217. 



Boveri. Sitz.-Ber. d. Ges. f. Morph. u. Phys. Munch. 



1888, Bd. IV. Verhandl. d. phys.-med. Ges. Wiirzb. 



1902, XXXV, p. 67. 

 Cockayne. Journ. of Genetics. 1915, V, p. 75- 

 Doncaster, L. Journ. of Genetics, 1914, IV, p. 11. 

 Harrison, J. Entomologist, 1916, XLIX, pp. 25 and 53. 

 Mehling. Verhandl. der physikalisch-medicinishen Gesell- 



schaft zu Wurzburg, 1915, XLIII, No. 5, pp. 174-236. 

 Morgan. Science, 1905, XXI, p. 632. American Natural- 

 ist, 1907, XLI, p. 715. Proc. Soc. Exper. Biol, and 



Med. 1914, XI, No. 6, p. 171. 

 Schultz, 0. Illustr. Zeitschr. f. Ent. II, 1897. 

 v. Engelhardt. Zeitschr. f. Wissenschaftliche Insekten- 



biologie, 1914, X, p. 161. 

 Whicher, S. Entomologist, 1915, XLVIII, p. 124, PI. VI, 



fig. 4. 



