72 THE ENTOMOLOGIST. 



transverse homy plates, only divided by a very narrow line ; 

 on the ventral surface, in the middle, a black triangular spot. 

 On the 2nd and 3rd segments (fig. 3) were two small black 

 spots ; and from this point the remaining segments gradually 

 became narrower and longer, each projecting anteriorly on 

 both sides on approaching the posterior margin of the 

 preceding segment. Along the middle of the dorsal surface 

 a black line was visible beneath the skin, broader at the 

 middle than at either end. The structure of the thoracic legs 

 was very remarkable (see fig. 4) ; they consisted only of two 

 horny knobs and a similar projecting s]5ot placed in a row, 

 the upper of the two knobs projecting a considerable distance 

 from the surface ; next to these was a brownish black spot. 

 The question arises, are these thoracic legs simply unde- 

 veloped, and do these projections indicate the joints ? If 

 this be so, as I think it is, then the largest and most 

 projecting knob will represent the last joint, to which, in the 

 case of other normally constructed sawfly larvae, the claw is 

 attached. On comparing this description with that given by 

 Boie and Zaddach of the larvae of the genus Fenusa, Leach, 

 it will be seen that these last offer many points of agreement, 

 but are specially distinguished — first, by the presence of five 

 pairs of abdominal legs ; secondly, by the normal structure 

 of the six thoracic legs ; and thirdly, by a single anal leg 

 under the last segment. 



After a short time the larvae betook themselves to a spot 

 on the leaf, at a little distance from that where they had 

 eaten out the parenchyma, each larva making a circular 

 depression, the walls of which were somewhat raised, giving 

 it an appearance of a blister on the leaf; both the walls 

 bounding this hollow in the leaf speedily became brown, as 

 represented at h in fig. 1 : in this circular space the larvae 

 passed the winter. 



It is extremely difficult to keep these little animals at the 

 requisite degree of moisture during the winter. Mr. Snellen, 

 who collected and kept o, large number of mined leaves, 

 was only able to send me two images reared from them, and 

 from all the leaves containing larvae, which I have kept in my 

 room for some consecutive years, not a single wasp has 

 appeared in the spring. I succeeded better with leaves 

 which I kept in the cellar, but the harvest was always 



