larvoi of tlie Tenlhrcdinldce. 199 



sides, and they project straight from the body. The 

 ground colour of these larvie is green, and the spines 

 are never so thick as to hide the coloration of the body. 

 AVith some species there are some Httle white hues 

 between the rows of spines. The larva? feed on the 

 upper side of the leaf; they are very sluggish and rarely 

 measure more than four lines. I believe these spines 

 standing up from the green body tend to conceal the 

 larvee, which do not look like living creatures at all ; and 

 this inanimate appearance is increased by the small re- 

 treating head. One or two species have the spines pale 

 green. 



There are many other points of similarity between the 

 larvEe of the Tenthredinidcs and Lej^idoptera which, if 

 time permitted, I should have liked to discuss, as well 

 as some others belonging more particularly to the Hy- 

 menopterous section. I may, however, say, that all the 

 conclusions arrived at by Weismann, in his work * on the 

 origin of the forms and colours of caterpillars of the 

 Spliingida apply Avith equal force to the TenthredmidcB. 

 That being the case, the cause or causes which jiroduced 

 the general similarity in the markings of the larvas of 

 saw-flies and of caterpillars must have been the same, and 

 that natural selection was one of the most proficient of 

 them will now, I think, be admitted by the majority of 

 naturalists. 



I may add, further, that Avhen young the larvas of 

 saw-flies are green and devoid of distinctive markings, 

 just as we find among moths. 



• Studien zur Descendenz-Theorie, ii. 



