SLUG-WORM. 325 



the three segments next to the head, and a pair of sucker- 

 feet on each of the other segments, exceptmg on the fourth 

 from the head and the tail-segment, which are footless.* 

 When feeding, they keep the end of the tail a little turned up. 



In four or five weeks these Slug-worms arrive at their full 

 growth, which is about half an inch in length, cast their dark 

 bottle-green skins, and appear as yellow or buff caterpillars, 

 free from all shine, and transversely wrinkled, instead of being 

 perfectly smooth. In the instance noted this happened at 

 the beginning of October, and the caterpillars shortly after 

 left the leaves and went down into the ground, where they 

 spun an oval brown silken cocoon covered outside with earth, 

 from which the Sawfiies came up in July in the following 

 year. 



The female fly (figured, magnified, at p. 324) is of a shmmg 

 black, tinged with violet ; the wings often stained with black, 

 with dark nerves, and a dark brown mark (the stigma) along 

 the fore edge. 



" The four anterior legs are brownish ochre, and the others 

 are more or less of that colour, but generally much darker ; 

 and the thighs, or at least the base, are pitch-colour."! 



This species of Sawfly was considered by Curtis to be the 

 Tcnthredo ccrasi of Linnaeus, but from subsequent record by 

 Prof. Westwood, of the nature of the perfect fly reared by 

 him from larvfe of the kind described above, it appears that 

 Tenthredo cerasi, Linn., is not the correct name, but (from 

 his own observations) Prof. Westwood became convinced that 

 the Sawfly under consideration is the Sdandria atra of 

 Stephens. I 



These points of nomenclature, however, do not appear in 

 any way to affect the practical matter of the life-history of 

 the infestation, and how to get rid of it. 



From the notice of " The Pear-tree Slug" published by the 

 Entomological Society of Ontario, it appears that the Saw- 

 flies are double-brooded in Canada. The flies appear in 

 May; the eggs are deposited singly in little slits cut for them 

 in the skin of the leaf by the ovipositor of the female, and 

 these produce a brood, coming out in the perfect state in 

 July ; from which a second brood arises, which is full-grown 

 in September or October. These remain in the ground 



* From other observations of the Sdandria (the genus to which this Sawfly 

 is now considered to belong), a small pair of caudal prolegs, making with the 

 others in all 22 pairs, were overlookea by John Curtis. 



t See " Slug-worm," by John Curtis, ' Gardeners' Chron.,' 1842, p. G92. 



\ See " Sawfiies of the Pear," by Prof. J. 0. Westwood, ' Gardeners' Chron.,' 

 1848, p. 524; and for further notes under the synonym of Eriocampa liviacina 

 see 'Brit. Phytophagous Hymenoptera,' by 1*. Cameron, p. 224. Observations 

 are also given, at pp. 22G and 228 of the same work, as to involvements of 

 nomenclature. 



