CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 1 49 



leaves. Ants carry lice to roots. Of no economic importance in 

 Ontario. 



Pea Plant-louse {Macrosiphum pisi Kalt.). — Green; eyes red; legs 

 long; migrates in August to clover fields where eggs are laid and first 

 spring generation feeds. Parasites — A phidiusjietcheri Ash., Megorismus 

 fletcheri Crwd., a chalcid. 



Potato Plant-louse {Macrosiphum solanifoUi Ashmead). — Green or 

 pink; migrates to the rose, where winter is spent. Feeds on a large 

 number of plants. 



Green Rose Aphis {Macrosiphum rosce Linn.). — A large pale green 

 aphis with dark antenna? and the cornicles long and black. Occurs on 

 roses. 



Black Chrysanthemum Aphis {Macrosiphum sanborni Gill.). — • 

 Occurs on chrysanthemums in greenhouses. A brownish-black pyri- 

 form plant-louse. 



COMMON SHADE AND FOREST TREE APHIDS 



Negundo Plant-louse {Chaitophorus negundinis Thos.). — A serious 

 pest of the ash-leaved or Manitoba maple in the West. Infested trees 

 soon become covered with honey-dew in which a sooty fungus develops. 



Woolly Apple Aphis {Schizoneura lanigcra).- — See above. 



Poplar Leaf Gall Louse {Pemphigus populicaulis Fitch).— Pro- 

 duces a deformity at the junction of petiole and blade of cottonwood 

 and aspen. 



Alder Blight {Pemphigus tessellatus Fitch). — A Woolly aphid, occurs 

 on branches of alder. Winged forms migrate to the maple. 



Beech Tree Blight {Pemphigus imbricaior Fitch).- — A similar form on 

 the twigs and leaves of beech. 



Sitka Spruce Gall Aphis {Chermes cooleyi Gillette), Western Hem- 

 lock Woolly Aphis {Chermes funilectis Dreyfus), Sitka Spruce Green 

 Aphis {Aphis abietina Walk.). — Are important economic forms on the 

 Pacific Coast of British Columbia. 



Spruce Gall Aphis {Chermes abietis Choi). ^Abundant locally on 

 White and Norway spruces, producing pine-apple-like galls at base of 

 terminal shoots. Each gall, ^ inch long, contains about 50 cells each 

 holding from 8 to 12 nymphs. The life-cycle is briefly as follows: 



"Galls open about mid- August and fully grown pupae emerge and 

 moult within a few hours becoming the winged form which deposits a 



