SYNOPSIS OF GALLS. 27 



13 (14) On Centaurea scabiosa. Large swellings on the stems. 



Aulax scabiosse. 



14 (17) On Potentilla. Irregular swellings as regards form and size 



on the leafstalks and stolons. 



15 (16) On Potentilla tormentilla. Xenophanes brevitarsis. 



16 (15) On P. reptans. X. potentillse. 



17 (18) On Nepeta glechoma. Irregular soft swellings on the stem 



and leaves. Aulax glechomse. 



18 (19) On Papaver. In the capsules, which may or may not be 



swollen. Aulax papaveris. 



19 (20) On Triticvm. Swellings on the roots. Aulax hieracii. 



20 (110) On the common oak (Q. sessiliflora or Q. pedunculata). 



21 (45) Situated on the under side of the leaf. 



22 (27) Round, soft, and succulent, green or white, often with rosy 



cheeks. 



23 (26) Appearing in the spring or early summer ; diameter not 



more than 6 mm. ; green, projecting a little through the 

 upper side of the leaf. 



24 (25) Smooth, glabrous, length 5 — 6 mm. Neuroterus baccarum. 



25 (24) Covered with long white hairs. Length 4 mm. N. tricolor. 



26 (23) Appearing in the autumn; whitish-yellow. Diameter 8 — 



12 mm. Dryophanta foli. 



27 (28) Oval or ovoid, smooth, glabrous, pallid green or yellow, or 



brownish -yellow, spotted with pink dots, moderately 

 hard, situated on the veins between two brownish sheaths, 

 which remain after the gall has fallen ; in August and 

 September. Andricus ostreus. 



28 (29) Reniform, small, green, succulent, usually crowded together ; 



September and October. Length 1 — 2 mm. 



Trigonaspis renum. 



29 (36) Semi- spherical ; hard and woody ; depressed at top and 



bottom. 



30 (31) Without gloss, the skin rough with projecting points, whitish- 



yellow, often with red rings or spots. Length 5 — 7 mm. 



Dryophanta longiventris. 



31 (30) Smooth, without warts or bands or reddish rings. 



32 (33) Gall with two chambers ; cylindrical -spheroidal, flattened 



above, with a raised point in the centre ; under side con- 

 cave. Dryophanta disticha. 



33 (32) Gall with one chamber. 



34 (35) Yery shining, broader than high, the sides usually more or 



less reddish ; larval chamber small, the walls thick. 



D. divisa. 



35 (34) Not very shining, higher than broad, the sides without red, 



the larval chamber large, the walls thin. D. agama. 



36 (29) Flat, lenticular, circular, often irregular. 



37 (38) Sunk, as it were, in the surface of the leaf, not projecting 



much on either side, circular, green, with striae proceeding 

 from the centre to the circumference ; May and June. 



Neuroterus vesicatrix. 



38 (37) Not sunk in the leaf, but attached to it by a point ; frequently 



gregarious ; in the autumn. 



39 (40) Round, depressed in the centre, covered with golden silky 



depressed hair. N. numismatis. 



40 (39) Flat, not covered with golden hair. 



