Variation in Lepidoptera. 465 
Notes on Imago. 
C.—constant. 
Species. Food-plant. Variation of Larva, 
Hadena pisi. |Erica; Spartium ;} Dark-green ; crimson. Rather 
Salix ; Pteris, &c. ; variable. 
perbaps  polypha- 
gous. 
Cucullia chamo- Anthemis. Pink ; green; yellow. C. 
mille. 
C, lychnitis. Verbascum nigrum Green ; yellow. C. 
and lychnitis. 
Heliothis marginata.| Ononis; Betula. Green; red; smoky. C. 
H, peltigera. Hyoscyamus ; Green; red ; uniform C. 
Ononis. or with pattern. 
Stilbia anomala. Graminacee. Green ; brown. C. 
Mr. Hellins then adds a list of species which, though very 
variable in the imago state, are constant or nearly constant in the 
larval. Among these may be cited Arctia caja, Hadena protea, 
Teniocampa instabilis, Anchoscelis lunosa, Apamea oculea, &c. 
A glance at the foregoing table will show that often when the 
imago is most constant, the larva shows the greatest tendency to 
variation ; this is especially marked in the species of the genus 
Eupithecia. To what then are we to attribute this variability in 
the larva? I have before expressed my doubt as to the effect of 
food in causing variation in the imago; not so, however, in the 
larva, for I believe that variability in the latter is caused in a 
great measure, but indirectly, by food, and that the object of such 
variation is, as Mr. Hellins has justly surmised in his letters to 
me, mimicry. Not that the larva of one species mimics that of 
another, but rather the plant on which it subsists. In fact the 
prevailing colours of the majority of Lepidopterous larve are 
green and brown, and admirably assimilate to those of the foliage 
and stems of plants and shrubs. This is especially noticeable in 
the majority of the larvee of Geometride, which are not strictly 
nocturnal feeders as are most of the Noctu@, which retire to some 
place of congealment during the day, when they would be the 
most liable to the attacks of birds. The larvae of many species 
of the genus Lupithecia show this power of mimicry to very great 
advantage. These are, for the most part, flower feeders, and 
have evidently the power of assuming the same colour as that of 
the flowers on which they feed. Some five years since I, one 
autumn, collected about a hundred larve of Eupithecia absin- 
thiata, and I remarked that when found on Senecio Jacobea, they 
