324 



PEAK. 



Slug-worm of Pear and Cherry Sawfly. 

 Selandria atra, Westwood; Tmthredo cerasi, Linu. (of Curtis). 



Tentltredo cerasi; Slugworra and Sawfly magnified, with lines showing 

 nat. length ; cocoon. 



The Slug-worms feed on the upper surface of the leaves of 

 the Pear and Cherry, clearing away the whole of the soft 

 substance of the leaf, so that the veins and the skin of the 

 lower side are all that remain ; they are also to be found on 

 Plum, Hawthorn, and Sallow, from the middle of August 

 until October. 



For all practical purposes the Slug-worms may be known 

 (when at their work of destruction) by their blackish or 

 bottle-green colour, together with their peculiar shape, and 

 the covering of slime or moisture exuding from their skin, 

 which gives them something the appearance of a Slug, but 

 still more that of a lump of wet black dirt fallen on the leaf 

 and run together at one end. They appear also to be known 

 by the sickening smell observable where many irees are 

 infested. 



In respect to the scientific definition of the species there 

 has been much difficulty, from some kinds of Selandria being 

 nearly alike in their perfect state (and probably in appear- 

 ance and habits whilst still " Slug- worms ") ; and consequently, 

 whilst there are many synonyms for one species, there is also 

 doubt whether two species are not given under one name. 

 Therefore, for clearness, I give the following note entirely 

 from the observation of John Curtis, attaching to it the name 

 he applied of Tentlircdo cerasi, and quote the description 

 of colouring of the legs of the Sawfly in full, as this is one of 

 the points requisite in determining the species. 



The Sawflies appear in July, and deposit their eggs on or 

 in the upper side of the leaf; these eggs are oval, and hatch 

 in a few days. The larva3 are of the lumpy shape figured 

 above, much the largest at the back of the head ; they are 

 furnished with ten pairs of feet, that is, one pair on each of 



