Hxplanation of Plates. 373 
overspread with grey mentioned on October 16th. The 
greyish appearance does not come out in the figure, the 
effeet being merely to render the brown of a paler tint. 
The larva was painted on October 17th. 
Fic.13. Larva at the same period and exposed to the same envi- 
ronments as that shown in Fig. 10. The description of 
Fig. 11 applies in every respect, except that the larva 
here represented was a specially dark example, and was 
painted on October 16th. 
14. Larva, nearly mature in the last stage, showing the effect 
of an environment of black-barked twigs up to the 
beginning of hybernation. During and after hybernation 
the larva was placed (I, B) in an environment of lichen- 
covered sticks, but, as the figure indicates, it had ceased 
to be susceptible to such influences, and no effect was 
produced. Before hybernation it had been one of the 
five darkest larva. The painting was made on May 19th. 
15. Larva at the same period and exposed to the same environ- 
ments (I, B) both before and after hybernation as that 
shown in Fig. 14. Although conspicuous white patches 
appeared on this and other larve subsequent to hyber- 
nation, it is improbable that this effect was due to the 
lichen which formed the surroundings after the begin- 
ning of hybernation. The comparison of the whole 
of the larvae indicates that they had then ceased to be 
susceptible to the colours of the environment. The 
larva was painted on May 22nd. 
EXPLANATION OF PLATE XVIII. 
Results of Experiments in 1893-4 upon the colour-relation between 
the larvee of Gastropacha quercifolia and their environment. 
All the figures are of the natural size, and all represent the 
natural resting position. 
All the figures represent the larvae in the last stage, and all but 
one nearly mature, in May 1894. 
Fia. 1. Larva of Gastropacha quercifolia, nearly mature in the last 
stage, showing the effect of an environment of lichen- 
covered sticks up to the beginning of hybernation, 
The lichen employed was probably Ramalina farinacea. 
During and after hybernation the larva was placed in an 
environment of black-barked twigs (II. G) which, it is 
