164 



INDIRECT INJURIES CAUSED BY INSECTS. 



from it feeds upon the kernel^ and, when about to become a, 

 pupa, gnaws its way through the cherry, and sometimes not 

 one in a thousand escapes.' This insect is fortunately rare 

 with us, and has usually been found upon the black thorn. 

 The cherry-fly also {Tepliritis Cerasi) provides a habitation 

 for its maggot in the same fruit, which it invariably spoils.^ 



The different varieties of the plum are every year more or 

 less injured by Aphides ; and a Coccus ( C. Persicce ?) some- 

 times so abounds upon them that every twig is thickly beaded 

 with the red semiglobose bodies of the gravid females, whose 

 progeny in spring exhaust the trees by pumping out the 

 sap. In Germany, as we learn from M. Schmidberger, while 

 the plum trees sufler from having their bark injured by two 

 bark-boring beetles (^Scolytus hcBmorrhous and S. Pruni)^ 

 their fruit is destroyed by the larvae of a beetle {Rhynchites 

 cupreus), of a moth {Carpocapsa nigricand), and of a saw- 

 fly ( Tenthredo Morio).^ 



The pear tree is liable to have its bark pierced in this 

 country by the larvas of Carpocapsa Wceberana, which often 

 lays the foundation of canker^; and in America by those of 

 two beetles (^^colytus pyri, and Strohi Peck^); its sap is in- 

 juriously drawn off' by Psylla pyri ; its leaves have their pa- 

 renchyma eaten away from under the cuticles, so as to give 

 them a blistered appearance, by the larva of the pretty little 

 moth Tinea Clerkella L. ; and while the blossoms are rendered 

 abortive by the attacks of the grub of a beetle (Anthonomos 

 pyri KoUar), the fruit is caused to drop off* prematurely and 

 rot by the larvae of not fewer than three minute tipulidan 

 flies, ( Sciara pyri Schmidberger, Sciara Schmidbergeri KoUar, 

 and Cecidomyia nigra Meigen'',) and also by that of a four 

 small w^inged fly, observed by Mr. Knight, which would seem 

 to be a saw-fly, and is probably the species which Reaumur 

 saw enter the blossom of a pear before it was quite open^ 

 doubtless to deposit its eggs in the embryo fruit. He often 



1 Trost Kleiner Beytrag. 38. 2 Reaum. ii. 477. 



3 KoUar on Ins. inj. to Gardeners, &c. 237. 232. 268. 



4 See Observations on this insect in Trans, of Hart. Soe. ii. 25. by W. Spence. 



5 Westwood, Mod. Classif. of Ins. i. 353. 



6 KoUar, ubi supr. 250. 289. 292. 



