APPENDIX. 



395 



This aphis has proved exceedingly destructive in several prune-growing 

 districts. Upon the first appearance of the lice the trees should be imme- 

 diately sprayed with the rosin wash recommended for young black scale, 

 care being taken to wet the underside of the leaves. Like all other aphis 

 they increase enormously, and a second spraying may be necessary later on. 



Tin: PEAR SLUG. 



{Ei-iocampoides limacina Retzius.) 



By Pkof. ('. L. Marlatt. 

 CHARACTERISTICS AND HISTORY. 



The damage to the foliage of the pear, cherry, plum, and allied ti-ees from 

 the slimy slug-worm is familiar to every fruitgrower. Two or three genera- 

 tions of these slug-worms, or "slugs, '" as they are also termed, appear during 

 the summer and frequently in such extraordinary numbers, with the later 

 broods, that the leaves of the attacked plants turn brown, die. and fall to the 

 ground in midsummer, and the 

 new growth of foliage which is 

 afterward thrown out is often 

 similarly destroyed. Trees thus 

 denuded are much checked in 

 growth or greatly injured, if 

 not killed. When the slugs 

 are very abundant, as they fre- 

 quently are in July during the 

 second brood, the sound of the 

 eating of myriads of mouths 

 resembles somewhat the fall- 

 ing of fine mist or rain on the 

 leaves, and instead of one or 

 two larv£e at work on a leaf 

 there may be upward of thirty; 

 Under such circumstances a 

 very distinct and disagreeable Fii 

 ordor is disseminated by the 

 multitudes of slimy slug-like 

 creatures. The slug-fly is a small, glossy black insect, considerably less in 

 size than the house-fly, measuring only about one-fifth of an inch in length. 

 The wings, which are four in number, are transparent, iridescent, and have 

 a smoky band across the middle, which varies in intensity in different speci- 

 mens. It belongs to the family commonly termed "saw-flies "( Tenth redi- 

 nidse ) on account of the saw-like instrument or ovijDOsitor with which the 

 female insect places its eggs in the leaves or other soft parts of the plant. 



. 1— Pear slug: a, adult saw-rty, female ; 6, larva 

 with slime removed ; c, same in normal state; d, 

 leaves with larvffi natural size; a, b, c, much en- 

 larged (original). 



