214 Dr. F. A. Dixey on 



form the nucleus of a most interesting and instructive 

 series to show the experimental evidence as to the proxi- 

 mate causes of seasonal dimorphism You will 



find some of the specimens from my Bijhlia experiments. 

 The few that emerged all bred true to their parents, but 

 the principal evidence consists in a slight, though constant, 

 colour-distinction which I found in the larvae of the two 

 insects, thus proving them to be distinct species." — 

 G. A. K. M. 



It is satisfactory to me to find that in consequence of 

 his latest experiments, Mr. Marshall now holds the view 

 as to the specific distinction between the two continental 

 forms of Bjjhlia which I felt justified in putting forward in 

 1898.* The specimens recently forwarded by him to tlie 

 Hope collection from Salisbury, Mashonaland, are as 

 follows : — 



A. B. ilithyia, Drury. A worn wet-season female. 



Captured March 17, 1901. Laid 3 eggs. Off- 

 spring : — 



Ai. Hatched March 21; pupated April 11; emerged 

 April 28. A wet-season female. 



A2. Hatched March 21 ; pupated April 11 ; emerged 

 April 29. An intermediate male. 



B. B. ilithyia, Drury. A worn wet-season female (Fig. 



1). Captured March 17, 1901. Laid 5 eggs. Off- 

 spring : — 

 Bi. Egg laid March 24; hatched March 28; pupated 



April 11 ; emerged April 29. An intermediate 



male. 

 B2. Egg laid March 24 ; hatched March 28 ; pupated 



April 11 ; emerged April 30. An intermediate 



female (Fig. 2). 

 B3. Egg laid March 24 ; hatched March 28 ; pupated 



April 11 ; emerged May 1. An intermediate 



male. 



C. B. gdtzius, Herbst. A worn wet-season female, of 



the form vulgaris, Stand. (Fig. 3). Captured March 

 24, 1901. Laid 6 eggs. Offspring :— 

 Ci. Egg, March 24 ; hatched March 28 ; pupated April 



* Proc. Zool. Soc, 1898, p. 37G. The current number (Feb. 1902) 

 of the "Entomolof^ist's Monthly Magazine" contains the first instal- 

 ment of a pa})erby Mr. Marshall in whicli he gives a detailed account 

 of his experiments in the breeding of Byldiii ilithyia and B. gotzius, 

 with descriptions of larva; and pup.-u. 



