588 Notes in 1887 upon lepidopterous larve, de. 
as would follow from the puncture through which the 
egg is inserted by an ichneumon’s ovipositor. UH, 
therefore, the marking originally possessed its present 
meaning, it is difficult to see why it should not be of 
the appropriate size—a size which would not need to 
be concealed during the protective attitude. 
The larva of Stawropus fagi therefore bristles with 
defensive structures and methods. When at rest it is 
concealed by a combination of the most beautiful 
protective resemblances to the commonest objects which 
are characteristic of its food-plant. Attacked, it defends 
itself by a terrifying posture, which is made up of 
many distinct and highly elaborate. features, all contri- 
buting to this one end. Further attacked by an insect- 
enemy, it reveals marks which suggest that it is of no 
interest to its enemy, for another parasite is already in 
possession. 
It may not unreasonably be objected that the larva is 
far from common, and that the small efficiency of the de- 
fensive measures throws doubt upon their interpretation. 
I have, however, already answered this objection in the 
case of the larva of Cerura vinula (Trans. Ent. Soc. 
Lond., 1886. pp. 158, 159). I argued then as I do 
now that such an “‘exceptional standard of defence was 
only attained by an exceptional need.” The means of 
defence have been the response on the part of the 
organism to the increasing attacks of enemies; and the 
latter, on their part, have met the response by increasing 
cunning or boldness. 
7. THE MEANING OF THE BLACK COLOUR OF THE EGGS 
or Paniscus cepHaLoTEs.—The shining black ova of this 
parasitic species are well known to every collector of the 
larva of Cerura vinula, for they are most conspicuous 
against the green background formed by the larval colour. 
Although the ova are partially hidden in the inter- 
segmental furrows, they are revealed at every movement 
of the larva, while some of them can usually be seen 
at all times. When Prof. Weismann was staying with 
me in the summer of 1887, I showed him one of these 
larve with the eggs affixed. This led to a discussion as 
to the meaning of the colour, in the course of which we 
both independently arrived at what I believe to be the 
correct interpretation, viz., that the colour is adapted 
