2i6 The Scottish Naturalist. 



The mites live in the furrow — usually a number in each gall. 

 They are pale orange in colour, and are large relatively to other 

 species of Phytoptus. I have found these galls in the woods of 

 Darnaway and of Cawdor, near Forres, in the end of September. 



Senecio aquaticus, Huds., and S. Jacob^a, L. — On these 

 plants occur very commonly flower-heads that appear fleshy, and 

 remain green, and do not flower, though reaching about twice 

 the normal size of flowering capitula. These effects result from 

 the presence of numerous larvae oi Diplosis Jacobcece, Loew, one of 

 the gall-midges. I have found these galls abundant wherever I 

 have looked for them, in the months of August and September. 

 On S. aquatiais I also found, near Ellon, the peduncles here 

 and there a good deal swollen and bent. In each swelling was 

 one larva of a Cecidomyia (?). Unfortunately I did not succeed 

 in rearing the insects. 



Ulmus MONTANA, Sm. — {o) Galls of Tetraneura iihii, L., on 

 the leaves. These galls are more like true galls in appearance 

 than are those of most Aphides. When fully formed, they pro- 

 ject from the upper surface of the leaf, usually on its apical half, 

 as oval bodies, y^,'^ % inch, attached to the leaf by a narrow 

 neck. The outer surface is naked, marked with shallow wrinkles 

 longitudinally, and yellowish green in colour. The leaf round 

 the base of the gall shows numerous yellowish-red spots, and 

 below bears patches of hairs, much like some Erineinn galls of 

 Phytoptus. The galls generally show an irregular opening on 

 one side near the base when mature, and through this the young 

 Aphides escape. I have found this gall in Scotland only once, 

 on a tree in the woods of Cawdor, last September. 



Investigation into the development of the gall shows that it is 

 due to the irritation produced by the attacks of the parent Aphis, 

 which, while the leaf is quite young, fixes on a spot on the lower 

 surface. Excessive development of tissue ensues, forming a 

 pouch, into which the insect is received, and the orifice of which 

 is entirely closed by a growth of hairs. 



{h) Pseudo-galls of Schizoucura ulmi, L. — These are similar to 

 the Aphis galls on geans and currants described above, and must 

 be familiar to many persons. Each consists of a leaf that is 

 usually spirally and unsymmetrically rolled backwards, one side 

 being less affected than the other. The upper surface becomes 

 irregular, as in the currant leaves, but remains green or yellow- 

 ish-green in colour. In texture the leaf becomes fleshy and 

 rigid. In the space enclosed by it live numerous Aphides, 



