lurvcE of the Tenthredinidai. 195 



of protective resemblance I have seen was with a species 

 of Nematus on the juniper. It could scarcely be seen, so 

 much did its body resemble the leaves. I need scarcely 

 say that many caterpillars of moths on the juniper have 

 the same colour. 



We have seen that the innocuous larvte are either flat 

 or cylindrical, the former feeding on the flat surface and 

 the latter along the edge. It is equally so with those 

 whi'ch smell badly.* Curiously enough, the flat larvae in 

 both the groups ai'e uniformly green, and have the same 

 sluggish habits, but there is a marked difference in their 

 ways of feeding. I have said that the edible ones feed on 

 the under side of the leaf. They eat the leaf quite 

 through, so that in a short time it becomes full of square 

 or roundish holes, the creature resting always on the un- 

 eaten portions. Now the others rest on the upper side. 

 They do not eat the leaf through and through, but only 

 the upper cuticle, so that when the larv^ have been feed- 

 ing for any period, the leaf becomes quite white, and the 

 larva3 are then not difficult to see. Now we find that 

 larva3 which have this habit are either covered with a 

 slimy secretion, as some species of Eriocampa, or they 

 emit bad odours, as is the case with some Nematides. 

 The larva of Nematus leucotroclius,\ for instance, which 

 feeds on the hawthorn, has an exceedingly bad smell. I 

 tried this larva with a Car ah us to see if the beetle Avould 

 eat it, but it would not do so, although afterwards it ate a 

 bit of a worm. 



The inedible larvae which feed along the edge of the 

 leaf are very different in coloration and habits from the 

 green margin feeders described above. Many of them 

 have a greenish tinge, but it is seldom or never of the 

 same tint as the leaf. Frequently it is bluish or sea- 

 green, or it may be whitish. Instead of the white or 

 pinkish stripes they bear irregular dots and marks, which 



* Although I have not made many experiments with the foul-smelling 

 larvae to see if they are rejected by insectiverous animals, still I think it 

 is allowable to conclude from the bad secretions they give out that this is 

 actually the case. 



+ These larvaj are very difficult to rear. I have only bred three females, 

 which unfortunately died in the cocoons before they got entirely rid of 

 the pupal skin. They are thus not easily identified, but the specimens 

 appear to agree in every respect with N. lencoti'ochnx. Brischke and 

 Zaddach figure (Schr. Ges. Konig. XVI. pi. 6, f. 5) a species of similar 

 habits and coloration under the name of JV. xanthopus, but as the descrip- 

 tion has not yet appeared, I can't say whether it is the same as mine or 

 not. 



