GALL MITES. 369 



CASE greenish-red galls, from the size of a hazel nut to that of a man's 

 fist, on the ground, on the rootlets, and also under the earth, on 

 Populus tremula. This certainly looks much liker the work of 

 some other insect than a mite ; but one can hardly suppose Dr. 

 Kirchner to have made a mistake of that kind. 



Phytoptus Sr. 

 According to Kaltenbach, this little white mite is invisible to 

 the unaided eye. It lives on the straggling bushes of the aspen. 

 It makes its appearance early; even when the swelling leaf 

 buds throw off their scales and the young twigs with the tender 

 little leave? appear, the numerous mites already begin their attack. 

 They appear on the young twigs, near the axil, then suck the un- 

 folding little leaves at the edge, which thereby get a thickened, 

 crinkled, somewhat rolled-up edge. At last, they lay hold of the 

 surface of the leaf and stop the development. The normal young 

 twigs so encumbered form numerous roundish wrinkled balls, until 

 the leaf is deformed past recognition. They are very crowded 

 round the shortened axil part. 



Kaltenbach found these striking monstrosities in the beginning 

 of July on a hedge in a meadow, in a light situation, and by sub- 

 sequent research noticed also the small originator of the deforma- 

 tion, besides single immature, wingless plant-hce on the healthy 

 leaves of the twigs and between the head of the leaves crawling 

 about, which, he says, had certainly no share in causing the mal- 

 formation. 



Erineum populinum, Pers. 

 Flat, pale green (4—10 of a millimetre long and 2—4 broad), 

 elevations of the upper surface of the leaf, the underside filled 

 with an extremely short Erineum, yellowish in the beginning, later 

 of a browner colour, harbouring a Phytoptus -ith of a millimetre 

 in length, rather conical, and reddish. Found on the aspen, bul 

 not in large numbers. 



A A 



