071 colour-relation. 219 



Total results of the foregoing experiments : — 



Colour. No. of larvffi. 



Dark brown approaching to black ... ... 3 



Brownish, shade unrecorded ... ... ... 3 



Brown, with green tinge ... ... ... 2 



Green ... ... ... ... ... ... 2 



Other coloura ... 



Total 10 



The change of colour in hoth sets of larvae became 

 perceptible at the commencement of the third stage of 

 larval life (after the second ecdysis), and the resemblance 

 to surroundings seemed to increase very gradually in 

 perfection up to the fourth ecdysis, after which the 

 colour underwent no further change, except the usual 

 and easily distinguishable darkening or alteration pre- 

 ceding pupation. 



My experiments with this species fully confirmed those 

 previously carried out by Mr. Poulton, and mentioned 

 by him in the 'Eeport of the British Association,' 1887, 

 p. 756, and in 'Nature,' vol. 36, p. 594, now being pub- 

 lislied in full. The larvre attained a really wonderful 

 degree of resemblance to their surroundings ; in the case 

 of my larvae with green surroundings this likeness was 

 greatly heightened by the touches of red, which exactly 

 matched the thorns and one side of the stem of the 

 young hawthorn shoot. 



The resemblance in shape, as well as colour, is ex- 

 tremely protective, the angular attitude of the larva at 

 rest rendering it almost indistinguishable from the twig ; 

 a fact also mentioned by Mr. Poulton (Trans. Ent. Soc. 

 Lond., 1887, p. 291). 



2. Notes on larvcB of Catocala nupta. 



In May, 1890, I procured, from Mr. E. Edmonds, of 

 31, Park Street, Windsor, 48 fertile ova of the Pied 

 Underwing Moth {Catocala nupta), with a view to making 

 experiments in colour-change, the species being recom- 

 mended to me for trial by Mr. Poulton. 



From May 27th to June 25th, 46 larvae hatched out, 

 and two of these died ; so that 44 remained for experi- 

 mental purposes. These I divided into three sets, giving 

 to the first set black sticks with the food-plant ; to the 

 second set green leaves only ; to the third green leaves 

 and white sticks, carefully peeled to remove the coloured 



