1887-88.] Galls of Norway. 217 



1. A paper of two pages by Steenstrup in Forhandlingars 



ved de skandinaviske Naturforskeres syvcnde Mode i 

 Christiania, 12-18 July 1856, pp. 189-190, entitled 

 Om de paa skandinaviske Traaer og andrc Planten 

 forekommcnde Traeemider (PhytojJtus, Duj.). (On 

 the Tree-mites occurring on the Scandinavian Trees 

 and other Plants.) 



2. Bnumeratio Insedorum Norvegicorum, by H. Siebke, 



begun in 1874, and still going on under the editorship 

 of J. Sparre Schneider. 



3. Bygaalen {Tylcnchus Hordci, n. sp,), by W. M. Sch0yen 



{Christiania Videnskahs-Selskahs Forhandlinger, 1885, 

 No. 22, pp. 1-16, pi. i.). 



Taking these in the above order, the first is known to me 

 only by a summary in one of the valuable papers by Pro- 

 fessor Thomas of Ohrdruf. In Steenstrup's paper he says, 

 with regard to galls of Phytoptus on Scandinavian plants, 

 " the peculiar hairy outgrowths which they (the mites) pro- 

 duce on the leaves of alders, birches, limes, elms, beeches, 

 walnut, species of maple, sloe, plum trees escaped from cul- 

 tivation, willotus, hazel bushes, wild thyme, bedstraio, &c.," are, 

 as regards form and situation, characteristic for each species. 

 He distinguishes between the chief types of mite-galls, e.g., 

 pouches, rolled leaves, hairy growths, &c. ; but does not enter 

 into details with respect to the special forms of galls on any 

 particular species of plant, so that it is uncertain which of 

 the forms of mite-galls he alludes to in the case of such 

 plants as bear more than one. He says also, with regard to 

 their origin, " the patches of hairs, e.g., on the beech leaves, 

 which have been taken for fungi, and described under the 

 genus Phyllerium, and the elegant folding of the leaves of 

 the hornbeam, have the same origin " as the other mite- 

 galls. 



In Siebke's Enumeratio there is no mention of the galls 

 made by any of the insects ; but I find the following species 

 enumerated as Norwegian, and as they are known to be 

 gall-makers in other countries, we cannot doubt that they 

 are so in Norway also. I have added the notes in brackets 

 to each : — 



