LIST OF ILLUSTRATIONS. 



XXI 



:?02. Foliage of larch injured 



by attack of Chermes . 329 



303. Chermes laricis on foliage 



of larch . . .330 



304. Chermes pini on stem of 



young Scots pine . 331 



305. Chermes pini on terminal 



shoot of Scots pine . 331 



306. Terminal shoot of Scots 



pine killed by Chermes 

 pini .... 332 



307. Chermes corticalis on branch 



of Weymouth pine . 332 



308. Chermes picecs on bark of 



silver fir . 333 



309. Hibernating winter forms 



of four species of 

 Chermes . . .334 



310. Under side of oak leaf in- 



fested with Phylloxera 

 punctata . . .337 



311. Apterous female, eggs, 



and larva of Phylloxera 

 punctata . . . 337 



312. Winged form of Phyllox- 



era punctata . . 33S 



DIPTERA (Two-winged Flies). 



313. 



Leaves of Salix viminalis 

 rolled by Cecidomyia 

 marginemtorquens 



Cecidomyia marginem- 

 torquens (male) . 



Cecidomyia marginem- 

 torquens (female) 



Shoot of hawthorn in- 

 jured by Cecidomyia 

 crakegi 



Twig of yew injured by 

 Cecidomyia taxi . 

 318. Shoots of Salix caprea in- 

 jured by Cecidomyia 

 rosaria 



Cecidomyia rosaria (male) 



Section of willow stem 

 showing injuries caused 

 by Cecidomyia salici- 

 perda .... 

 321. Portion of bark and wood 

 cut off to show the 

 injuries of Cecidomyia 

 saliciperda . 



314. 



315. 



316. 



317. 



319. 

 320. 



343 



344 



344 



345 



345 



346 

 346 



347 



34: 



322. Leading shoots of a species 



of willow injured by 

 Cecidomyia heterobia . 349 



323. Twig of Salix caprea in- 



jured by Cecidomyia, 



sat iris . . . .350 



324. Cecidomyia salicis (male) . 350 



325. Leaf of lime-tree injured 



by Cecidomyia tiliam 

 volens . . . .351 



326. Shoots of lime-tree injured 



by Cecidomyia tiliam 

 volens . . . .351 



327. Foliage of ash injured by 



Diplosis botularice . 352 



328. Edges of oak leaves folded 



by Diplosis dryobia . 352 



329. Galls on leaf -stalks of 



aspen poplar caused by 

 Diplosis tremul'i . . 353 



330. Galls on upper surface of 



beech leaves caused by 

 Hormomyia piliger . 354 



331. Leaves of goat willow 



galled by Hormomyia 

 caprea? . . . 354 



332. Galls on broom caused by 



Asphondylia sarothamni 355 



333. Asphondylia sarothamni . 356 



334. Pupa of Asphondylia saro- 



thamni . . . 356 



335. Gall on stem of bramble 



caused by Lasioptera 

 rubi . . . .356 



336. Galls on stems of willow 



caused by Agromyza 

 schineri . . .357 



337. Leaf of snowberry mined 



by Chromatomyia ob- 



scurella . . . 359 

 33S. Leaf of holly blotched by 



Chromatomyia ilicis . 359 

 339. Bibio marci (males and 



females) . . .361 



PSYLLID^:. 



340. Leaflets of ash injured by 



Pxyllopsis fraxini , 365 



341. Leaves of box injured by 



Psylla buxi . . .366 



342. Young form of Psylla cra- 



tcegi .... 367 



