upon lepidopterous larva, dtc. 295 



for not only are the colours of the leaves faithfully 

 reproduced, but the characteristic orange berries are 

 represented by an orange spot at the base of the caudal 

 horn upon each side, as was pointed out by Weismann, 

 and as I can confirm from my experience of the larva 

 at Visp in Switzerland. In the case of Rumia cratcegata 

 it is similarly possible to affirm that hawthorn is the 

 food-plant with which the larva has been longest 

 associated out of the several species of plants upon 

 which it also occurs. On Plate X., fig. 5 (natural size) 

 a drawing was made of a living example of this larva 

 as it rested upon a twig of hawthorn. It is at once 

 seen that the dorsal tubercles placed on about the 

 middle of the length of the larva very faithfully repre- 

 sent a superficially similar structure upon many of the 

 side twigs of the food-plant. Not only do these pro- 

 jections occur towards the middle of the length of the 

 twigs, but they are situated on the angle of a slight 

 bend, a character which is also reproduced in the larval 

 form. Furthermore, the mode in which the different 

 varieties of the larva are coloured is almost exactly the 

 same as in the varying twigs of this plant. The bark 

 is covered by a thin superficial layer which is of a bluish- 

 grey colour, while the deeper layers beneath are brown, 

 or green, or mixed brown and green, becoming visible 

 over a large part of the surface owing to the breaking 

 away of the former layer. Hence the colour of the 

 branches is brown or green, mottled with grey, and not 

 only is this the exact appearance of the larva, but the 

 way in which the colours are blended is precisely similar 

 in the animal and the plant. The darker colours of the 

 larva may be brown, or green, or mixed brown and 

 green, mottled in all cases with bluish grey. Such 

 remarkable specialisation to the details of single food- 

 plant certainly warrants the suggestion that the associa- 

 tion is very ancient, — that Cratcegus is the ancestral food- 

 plant of Humid cratcegata. 



1. A FURTHER ACCOUNT OF THE DEFENSIVE STRUCTURES 



of the larva of Dicranura vinula. — In my last paper 

 ! Trans. Ent. Soc. Lond., 1886, Pt. II., June, pp. 156—158) 

 I gave an account of defensive appearance and habits of 

 the larva of D. rum In. I am now able to give a figure 

 of the larva in the terrifying attitude (see Plate X., 



