upon lepidopterous larva, <(V. 317 



and under all circumstances it is controlled by that 

 other sense which enables the larva to recognise its 

 food-plant as soon as it reaches it. 



Description of Plate X. 



Fig. 1. Natural size. The mature larva of Smerinthus 

 ocellatus, seen from the right side. The larva was found on 

 S. triandra, and possessed the most developed system of red 

 spots which I have yet seen. The figure shows that all three rows 

 were highly developed, the upper row being represented on every 

 segment anterior to the 8th abdominal ; the middle row possessing 

 in addition a spot upon the latter segment, while the lower row 

 was quite complete, all the claspers being distinctly marked. 



Fig. 2, x 2 diameters. The head of a mature larva of 

 Smerinthus populi, seen from the right side. The patches of dark 

 shading upon the head indicate the position of the red markings. 

 The larva possessed a remarkably developed system of red spots, 

 which extended on to the head itself in the positions shown in the 

 figure. The chief masses are seen to be in the area of the ocelli, 

 represented as a semicircle of black points, and on the apex of the 

 head. 



Fig. 3. Natural size, seen from the right side. An apparently 

 mature Chserocampoid Sphinx larva, brought from Celebes by 

 Dr. Hickson. The larva combmes, in an interesting manner, the 

 characteristics of many genera of Sphingidce. The well-formed 

 eye-like mark on the 1st abdominal segment, together with the 

 correlated form of the anterior part of the body and the head, 

 rendering possible the well-known terrifying attitude, — all are as in 

 Chcerocampa. The oblique stripes, with their dark borders, the 

 traces of shagreening, and the subdorsal persistent for its whole 

 length, especially resemble Smerinthus and the younger stages of 

 Sphinx. The shape of the caudal horn is peculiar, but recalls that 

 of the latter genus, while the fact that the shagreening is far 

 more prominent upon this structure than upon any other part of 

 the body also obtains in other genera, although it is perhaps most 

 characteristic of Acherontia. The white dorsal and lateral sjiots 

 are probably very ancestral features recognisable in the younger 

 stages of Sphinx and Smerinthus. The living larva was green in 

 colour. 



