2516 The Zoologist— March, 1871. 



its method of gnawing the leaf. A larva, at this stage, is repre- 

 sented at fig. 6. The head was olive-brown; mandibles dark 

 brown; the eyes seated in brownish black spots, — these were 

 round, with a prolongalion in the direction of the neck ; on the 

 head were a few white hairs. The body had twenty feet; the 

 thoracic legs were brownish green, with a blackish line on the 

 first joint, and were terminated by brown claws. The body was 

 greenish on the back, pale at the insections of the rings and at 

 the neck ; the sides, the ventral surface, and the abdominal and 

 anal legs being bright green ; there were some little hairs on the 

 back. The trachea) could be seen through the skin ; the stigmata 

 were white. Above the second and third pair of legs, on either 

 side in the dark green, was a small, round, pale green wart. The 

 dentate anal valve was the chief characteristic ; this is now seen 

 to have eight projecting points, and is represented at fig. 7 in 

 profile. The larva now ate holes in the fresh alder leaf, in the 

 manner represented at fig. 8. After the following or last moult it 

 slowly consumed the space between the hole and the margin of the 

 leaf The peculiar manner of feeding at different periods of its 

 existence had also struck my friend Wttewaall, who has preserved, 

 in his entomological herbarium, several alder leaves, which had 

 been attacked by larvae of this species. Among them is a leaf, to 

 which the following notice is attached : " the caterpillars of this 

 species eat first channels (like our fig. 2), and then quit the leaf to 

 eat out broader pieces from another." I, however, once found a 

 leaf, in which the same caterjnllar seemed to have eaten out 

 channels of both patterns. 



After the last moult, when the larva consumes the leaf up to the 

 margin, it assumes the appearance represented at fig. 9. It is then 

 yellowish green, the first and last two segments being yellow. The 

 head is olive-brown, with a round black spot on either side, in 

 which is placed the shining black eye (see fig. 10). The mandibles 

 are brown ; the thoracic legs pale green with black claws. The 

 anal valve has eight points. There are eight pairs of abdominal 

 legs, — thus twenty-two in all ; whereas before there were but 

 twenty. I consider myself quite certain upon this point, although 

 I mention it with some appearance of doubt : it has been hitherto 

 quite unknown among the sawflies that an additional pair of legs 

 should be developed at the last moult. When one reflects, however, 

 bow difficult it is to see the last pair distinctly, — in the genus 



