72 THE FAUNA OF SCOTLAND. 



25 (24) The surface glabrous, irregularly ribbed or keeled longitudin- 



ally, green; length, 4-5 mm.; in June and July, 



Amlricus marginalis. 



26 (27) An irregular, often globular or oval swelling at the base of the 



leaf; green, smooth, a large central cavity containing a small 

 brown ovoid seed-like inner gall not attached to the outer 

 shell ; May and June, - - Andricus (curvator) collaris. 



27 (28) A small swelling (2-3 mm. in length) on the midrib, green, 



projecting through both sides ; in August, 



Andricus (testaceipcs) Sieholdii. 



28 (57) In the leaf-buds. 



29 (30) Polythalaraous, large (often 1 inch and more in diameter), 



whitish-yellow, soft and spongy, in the terminal buds ; May 

 and June, - - . . Biorliiza (terminalis) aptera. 



30 (29) Monothalamous, not spongy in texture. 



31 (35) In twigs on the trunk or near the ground. 



32 (33) Roundish, soft, juicy, bare, whitish-yellow, often reddish, 



usually found near the ground among moss, &c. ; in May. 

 Length 5-7 mm., - - - . Trigonci'^ins iimjaptera. 



33 (34) Oblong, shortly pilose — on adventitious buds near the foot of 



the tree. Violet, sometimes bluish-green, covered with a 

 very short velvety pale pubescence ; in June, 



Dryoplianta (Tasclienhergi) foUi. 



34 (33) Greenish, or greyish-green, covered with longish (comparatively) 



white hair; in May and June, Dryoplianta (similis) longirentris. 



35 (59) In twigs on the branches. 



36 (37) Large, round, marble-like, greenish-yellow ; when young with 



red cheeks, brown when old, not falling down; in August, 



Cjjnips Kollari. 



37 (36) Small, dropping oflf when mature. 



38 (39) Covered wdth a dense covering of brownish-white hair; spindle- 



shaped; length, 5-8 mm. ; July, - - Andricus soUtaria. 



39 (38) Bare, not covered with woolly hair. 



