on colour-relation. 217 



time the l;irv;ie began to show signs of change of coloiu-, 

 and became greenish in hue, the original colour having 

 been varying shades of brownish grey or dusky brownish 

 green. 



July 18th. — Length of largest larva, 14 mm. Two 

 larvns disappeared, probably having escaped through 

 some crevice, or been lost in changing the food. 



July 19th. — The third ecdysis took place. The 

 nine larva) left showed a distinct change of colour to 

 green. 



July 22nd. — All 9 larvpe were of shades of green or 

 greenish brown. They varied a good deal in shade ; 

 three were very bright green, exactly matching the 

 leaves of the food-plant, and had the dorsal tubercles, the 

 head, and the thoracic legs of a crimson-red, perfectly 

 corresponding to the colour of one side of the hawthorn- 

 shoots and of the thorns. The other six were of a green, 

 more or less bright, and all were touched with red on 

 the parts above mentioned. None were brown, or even 

 brownish green. 



July 26th. — The fourth ecdysis occurred. 



July 27th. — I drew the brightest green larva, namely, 

 that figured in PL XL, fig. 1. 



July 31st. — One of the larvae left off feeding, and 

 mounted to the roof of the cylinder. 



Aug. 2nd. — A second larva did the same; and by 

 Aug. 22nd all the larvte had pupated, spinning pinkish- 

 white cocoons in close proximity to each other on the 

 roof of the cylinder. 



The total results of the experiment with these 9 larvae 

 were as stated below : — 



Colour. No. of larvffi. 



Brilliant green ... ... ... ... ... 1 



Li<i:hter greeu, but very bright ... ... 2 



Duller shades of green ... ... ... ... 6 



Brown and other colours ... ... ... 



Total 9 



Of the 22 larvffi divided on July 7th, 11 were placed in 

 cylinder 5, and reared among dark surroundings. They 

 were supplied, from the time of separation, with haw- 

 thorn from the same tree as that used for the larvae with 

 green surroundings. But in this case older twigs were 



