THE PEAR. 



471 



Schmidberger, Sciara Schmidbergeri Kollar) is 

 similar in its effects to the last, differing little 

 from it except in size. We are not aware of any 

 means being taken for the suppression of either. 



The slug-worm, or slimy caterpillar (Selandria 

 atra Stephens, not Tenthredo cerasi of Linn., 

 nor T. celhiops of Fab.), fig. 201, is a well-known 



Fie\ 201. 



ated, with a view to make it more adhesive ; 

 and tobacco-water has also been employed, ap- 

 plying it both early in the morning and late in the 

 afternoon. We think, however, the application 

 would be more effective if used during the night, 

 at which time the insect is traversing the foliage, 

 and unprotected by it. Dusting the trees late in 

 the evening with caustic lime is a much more 

 effectual remedy, and of more easy application. 



The large pear as ty ages — A sty ages (Coleo- 

 phora) hemerobiella — fig. 202, although very 



Fig. 202. 



SLUG-WORM AND PERFECT INSECT. 



insect, so far as its effects are concerned, to 

 those who cultivate the pear and the cherry, for 

 it is equally injurious to both, often stripping 

 the trees of their foliage. In their caterpillar 

 state they are both singular and inactive, repos- 

 ing upon the foliage more like black slugs or 

 young tadpoles than the larvae of a sawfly. 

 Their being also covered with a moist slimy mat- 

 ter gives them the appearance of the excrements 

 of birds. The caterpillar has six pectoral, and 

 fourteen abdominal, but no anal feet ; the whole 

 body is of a deep bottle-green colour, thorax 

 very much dilated, nearly concealing the whole 

 head. They feed entirely on the upper sides of 

 the foliage, retreating beneath the leaves during 

 the day, and wandering about during the night 

 in search of fresh food. They cast off their 

 bottle-green skins when about a month old, and 

 afterwards appear in a coat of a buff colour, 

 which has led to their being considered, in this 

 state, as a distinct insect. Shortly after this 

 change they quit the trees, and retreat under 

 the earth, where they repose till about the end 

 of July the following year, when they emerge in 

 their fly state, and commence the process of re- 

 production. Ruricola, in " The Gardeners' Chro- 

 nicle," observes, in describing this insect, that 

 he is inclined to believe that there may be two 

 sorts of this genus which feed upon pear-leaves ; 

 for towards the end of July he had some dull 

 ochreous larvae sent to him, eating the leaves 

 in the usual way, with black heads only ; and 

 when they changed their skins, they became en- 

 tirely of a deep ochreous colour. The natural 

 enemy to the slug-worm appears to be a minute 

 very hairy species of Acarus, or spider. The 

 artificial means for their suppression is syringing 

 with lime-water in which soft soap is incorpor- 



LARGE PEAR AST VAGES AND GRUB. 



destructive to the foilage of the pear in some 

 seasons, seems to be of periodical develop- 

 ment, appearing in vast numbers in one season, 

 and scarcely to be found in others. The cater- 

 pillars are enclosed in a dark- coloured, nearly 

 cylindrical case, about half an inch in length, 

 having both ends open; out of the lowermost 

 end the head of the caterpillar is from time 

 to time protruded ; while from the upper end, 

 which is somewhat elastic, the insect discharges 

 its excrement. The caterpillar is of a pale- 

 brown colour ; the head small, and deep black ; 

 the sides are flesh-coloured, with small dark 

 spots ; the segment immediately behind the 

 head is black, hard, and glossy, with a palish 

 line down the middle ; the two next segments 

 have a small black triangular spot near the 

 margin, and a smaller dark dot on each side, 

 above the legs. The remaining segments, with 

 the exception of the last, are destitute of reflexed 

 hooks ; while the last has a pair of prolegs on 

 the under side, the whole of this segment being 

 covered with a black scaly patch. This cater- 

 pillars mode of feeding is different from that of 

 most others, its mouth being brought into close 

 contact with the under surface of the leaf : the 

 insect, ensconced in its cylindrical covering, 

 seems to stand erect, or at right angles with 



