332 Professor E. B. Poulton on colour-relation 



Experiments upon the Larvjs of Gastropacha 



quercifolia (1898-4). 



On July 22nd, 1893, Mr. W. Holland found a company 

 of young larva;' of this species crowded together towards 

 the end of a shoot of hawthorn near Steeple Aston, Oxford- 

 shire. They were all the same size, and had evidently not 

 long before hatched from a single batch of eggs. Thus was 

 afforded the opportunity of trying another set of experi- 

 ments upon a larva which is known sometimes to assume 

 a lichen-like appearance. Furthermore, there was the 

 additional interest of testing larval susceptibility to en- 

 vironment before, during, and after hybernation. The 

 food-plant employed throughout was hawthorn. The 

 present writer is responsible for the starting of the experi- 

 ments, the arrangements for hybernation, and thecomparison 

 of larva' on September 21 st, October 3rd to November 3rd, 

 March 2Gth, April 27tli, May 7th and 25th. The other 

 records were chiefly made by Mr. W.Holland, in much less 

 part by the present writer. 



I. G. quercifolia. 



July 28//!., 1893. Fifteen larvae of quercifolia placed 

 with intensely black twigs of the Turkish oak {Quercus 

 eerris), intermixed with their food-plant, hawthorn. They 

 were re-fed and examined on the following dates. 



Attgust 1st. Twelve larvoe on the green leaves and 

 shoots, 3 on the black twigs. All blackish-grey in colour. 



August 5th. Four larvae on the leaves and shoots, 11 on 

 the black twigs. 



Au.gust 9tJi. Three larva; on the leaves and shoots, 12 

 on the black twigs. 



August IMh. Fifteen larvte counted ; all on the black 

 twigs. The colours were black and white with a little 

 grey. 



August 19/ A. All 15 larvge on black twigs. 



August 22nd. All 15 larvse on black twigs. 



August 21st. All 15 larva? on black twigs. The larva' 

 were now much blacker, but white markings were still 

 present, 



Se])temher 4<th. Fifteen counted. 



Se2)tembcr 7th. Fifteen larvse on black twigs. 



Sqjtemher 0th. Fifteen larvjB on black twigs. 



