1886. ] Larva of Smerinthus ocellatus and its Food-plants. 149 



paper was written, nearly all the evidence seemed to point the other 

 way. The larvae of this set were intermediate, inclining in some cases 

 to the yellowish side. Hence the effects are the same as those pro- 

 duced by leaves which are known to cause the yellowish varieties as a 

 rule. These results can be compared with no previous experience, as 

 the larva has never been bred upon this tree (as far as I am aware), 

 and I can find no instance recorded of its being found in the field 

 upon this food-plant, except the instances which occurred in 1885 (to 

 be described). These agree with the breeding experiments, as does 

 the result of an experiment given in my last paper (quoted above, 

 p. 303), in which S. triandra modified the colour of a whitish larva 

 found upon 8. ferruginea. 



Salix triandra (No. 16, without the whitish bloom on the under 

 sides of the leaves). — These results compare in a very interesting 

 manner with those of the last set, the influence in the direction of 

 yellow being more strongly marked than in the case of the usual 

 leaves of this plant. The numerous larvae of these two sets were 

 repeatedly placed side by side and compared in the most careful 

 manner, and there could be no doubt that there was a considerable 

 difference in the predominance of yellow, while the larvae had been 

 subject to exactly the same conditions, except in the one point men- 

 tioned above. 



Salix babylonica (No. 17). — The larvae were all well on the yellowish 

 side of intermediate (except the one which was put upon another food 

 when quite young), and this result compares favourably with that of 

 the larvae of Series I upon the same plant (No. 3), where with the 

 greater hereditary influence towards white the larva became an inter- 

 mediate variety. In this case also the larvae of the two series were 

 examined side by side, so that there was no doubt about the difference. 

 This result also compares favourably with the larvae captured upon 

 this food-plant during 1884. 



Salix rubra (Nos. 18 and 19). — These results also compare well 

 with No. 4 of Series 1. As far as it was possible to judge from the 

 immature condition of the larvae in the latter set, the effect was not so 

 yellow as in Series III. The effect produced in the present case was 

 stronger than in the larvae from the same set as the parents, which 

 were fed upon S. rubra. This was to be expected, because the 

 tendency of the latter was very strongly towards the white variety, 

 while in the present instance it was somewhat modified. 



Series IV. 



Eggs were* laid by a female moth, bred from a larva, which had 

 been fed in 1884 for the whole of its life upon Salix cmerea, and 

 which became an intermediate variety. (The larva was one of those 

 mentioned on p. 300 of the paper quoted.) The eggs were fertilised 



VOL. XL. m 



