NATURAL HISTORY SOCIETY OF GLASGOW. 353 



bodies to the food plants, so that in this way they were not 

 easily noticed, while it was found that larvae of this class were 

 readily eaten by birds and other animals. On the other hand, 

 larvae which possessed noxious properties were so coloured and 

 marked as to be readily seen ; and these, too, fed openly. A 

 third class again escaped destruction by their curious and grotesque 

 shapes, although otherwise they were harmless. Proceeding to 

 apply this theory (which had been only hitherto done to the 

 caterpillars of lepidoptera) to the larvae of sawfiies, Mr Cameron 

 said that the flat larvae which fed on the upper side of the leaf 

 were green, but as they ate only the upper epidermis, the leaf in 

 this way became quite white, which rendered them visible, while 

 they gave out either a foul smell, or were covered with a resinous 

 exudation. The flat larvae which fed on the lower side of the 

 leaf ate the leaf through and through, and possessed no bad 

 qualities. Again, with the margin feeders innocuous larvae were 

 green, and if they had any markings these took the form of white 

 or pink continuous lateral or dorsal lines, which, no doubt, 

 represented shadow lines. They also in feeding followed the 

 outline of the leaf or the portion eaten out with their bodies 

 which were closely pressed to the edge. Noxious larvae, on the 

 other hand, were marked with contrasting colours and marked 

 with various irregular markings or lines, while they fed with the 

 after part of the body extended in the air. Alluding to the habit 

 these larvae have of keeping their bodies in a state of agitation, 

 Mr Cameron suggested that this was for the purpose of keeping 

 away ichneumons, a view confirmed by his having seen an 

 ichneumon driven away by the larvae of Croesus sej^tentrionalisj 

 by actively whipping their bodies. Various individual cases of 

 protective resemblance were mentioned in the paper, and allusion 

 was made to some of the active and passive means of de- 

 fence possessed by difterent larvae. 



X. — On two new sjiecies of Carboniferous Pohjzoa. By Professor 

 John Young, M.D., and Mr John Young, F.G.S. 



[ Read October 30th, 1877. ] 



In a former Part of the Transactions of this Society, Vol. II., 

 p. 325, we described seven species of what we considered to be 

 new forms of Glauconome, from the Carboniferous limestone 



