302 The Scottish Naturalist. 



24. A. solitaria, Fonsc, spindle-shaped bud-gall. Rare, in 



Clyde district. 



25. A. marginalis, Adler, on edges of leaves. Common. 



26. A. quadrilineatus, Htg., on catkins. Common. 



SCOTTISH OAK GALLS- 



By Professor JAMES W. H. TRAIL. 



THE following is an attempt to supply a useful key to deter- 

 mine to which species of the gall-makers any of the galls 

 likely to be found in Scotland belongs. It is confined to those of 

 the Cynipidae, with the exception of two galls of gall-midges at the 

 head of the key. In it are included the galls of all the insects 

 in Mr. Cameron's list, in both forms ; though I am not aware that 

 both forms have been detected in Scotland in all the species in 

 which they are believed to occur on the Continent. In construct- 

 ing the key, I have made considerable use of Mr. Cameron's 

 synopsis in the " Fauna of Scotland, Hymenoptera ; " but I have 

 endeavoured to work out a more simple and complete arrange- 

 ment than it follows. I trust that this effort may assist beginners 

 in the fascinating study of the oak galls. As regards those names 

 with one word in brackets, e.g. A. (noduli) radia's, the name in 

 brackets is that by which the form of gall under notice was 

 originally named ; and the last name is that by which both broods 

 of the insect are now known. 



1. Open pseudogalls in leaves and leafy buds (of Gall midges), 2. 

 True galls, with closed cavities (of Cynipidae), 3. 



2. Leaves of bud stunted and twisted, with larvae between f hem. 



Cecidomyia Quercus Binnie. 

 Lobes of full-grown leaf folded backwards, and slightly fleshy, 

 and pale. C. (Diplosis) dryobia F. Lw. 



3. On roots, 4- 

 On stems, 5. 

 In twigs or young branches, 6. 

 In buds, 7. 

 On leaves, 22. 

 On catkins, 37. 



