IN DEFENSIVE COLORATION 341 



season ocellated phase of Precis almana, the aster ie form, 

 is the only one found in the permanently damp forests of 

 Siam. The wide experience of Mr. T. R. Bell in North 

 Kanara has led him to the belief that a larval food 

 consisting of young succulent leaves containing abundant 

 moisture, is the condition determining the wet season 

 forms of the dimorphic butterflies that have come under 

 his observation.^ (See also pp. 311, 312.) 



Mr. Marshall also considers that the under surface of 

 the wet season Nymphaline butterfly, Byblia gotzucs is 

 mimetic of the Acraea serena type of pattern, while the 

 under surface of the dry forms of it and B. ilithyia is 

 Procryptic- An intermediate ilithyia and 3. dry gotzius 

 bred by him from the eggs laid by wet season females 

 are figured, together with the respective parents, by 

 Dr. Dixey.' In order to realize the general resemblance 

 of these latter to an Acraea it is necessary to imagine 

 the fore wings almost entirely covered by the hind, as in 

 the attitude of repose. The application in the early wet 

 season of dry warmth to the pupae of ilithyia caused 

 a butterfly to approach the dry season type.^ 



Dr. Dixey has stated that, while the under surface in 

 both sexes of Teracolus regina is clearly Procryptic in the 

 dry season, it is in mimetic association with certain un- 

 described forms of Bele^iois in the wet.^ 



6. Seasonal Transitioii in degrees of Synaposeniatic 

 Defence, or from Aposematic to Synaposcmaiic Defence. — 

 Dr. F. A. Dixey has recently described the following inter- 

 esting seasonal changes of Ethiopian Pierinae.^ The dry 

 season male oi Belenois thysa is a much better mimic of the 

 male of Mylothris agathina than is the wet season male ; 

 while the female thysa is an excellent mimic of the female 

 agathina in the dry season, but does not mimic it at all 

 in the wet. The Mylothris model shows no seasonal 



^ Eiit. j\lo. Mag., 1906, p. 122. 



'^ Ent. Mo. Mag., 1902, p. 49. 



^ Trans. Ent. Soc, Lond., 1902, p. 189, pi. iv. 



* Jrans. Ent. Soc, Lond., 1902, pp. 202, 203. 



° Proc. Ent. Soc, Lond., 1906, pp. xcvi, xcvii. 



^ Proc Ent. Soc, Lond., 1906, pp. xxxvi, xxxvii ; 1907, pp. xxiii, 

 xxiv. 



