496 



Nalepa (A.). Die Systematik der Eriophyiden, ihre Aufgabe und 

 Arbeitsmethode. Nebst Bemerkungen uber die Umbildung der 

 Arten. [The Taxonomy of Eriophyids, their Definition and 

 Technique. With Observations on the Re- arrangement of the 

 Species.] — Verhandl. k.k. zool.-bot. Ges., Vienna, Ixvii, 1917, 

 pp. 12-38. (Abstract in Zeitschr.f. Pflanzenkrankheiten, Stuttgart, 

 xxviii, no. 1-2, 1st February 1918, pp. 76-78.) 



The view that similar galls on difierent species of plants are due 

 to different gall mites may prove to be incorrect. A comparison 

 of the mites producing similar galls on allied host-plants will show 

 the need of withdrawing many species now thought to be distinct. 

 For instance, Erineuin oxycantliae and E. malinum are due to the 

 same mite — Epitrimerus goniothorax, Nal., and E. malinus, Nal., 

 cannot be considered a separate species. On the other hand no species 

 of mite has been observed to produce similar galls on non-allied plants. 

 If different galls are present on one' and the same leaf they must 

 be considered to be caused by different mites. Dissimilar galls on 

 the same host-plant are generally produced by specifically different 

 mites, though this is not a universal rule, A great increase of 

 individuals may lead some of them to modify their habits and to migrate 

 to plant-organs not previously infested, giving rise in them to dissimilar 

 galls ; this dissimilarity is j)robably due to a difference in the irritation 

 set up; Widely dissimilar galls on plants belonging to the same 

 plant-group are due to mites which are sometimes so similar morpho- 

 logically that their genealogical relations are easily seen. For instance, 

 nearly all the plant-galls of conifierous trees belong to the form-group 

 of Eriophyes pini. 



In order to clear up confusion two facts rhust be considered :— 

 (1) Forms of the same type-species produce similar galls on various 

 species of the same natural plant-family. The differences seen in the 

 blister-mites of Pyrus, Sorbus, Cotoneaster, Crataegus, Cydonia, etc., 

 cannot be recognised as specific characters. In the case of Sorbus 

 aria and S. aucuparia these mites may show greater differences, for 

 there is a physiological difference in that each variety can exist only 

 on the species of host-plant peculiar to it. This view is supported 

 by the fact that leaf-blisters are not found on Crataegus oxyacantha 

 in the Vienna forests where this plant grows together with Pyrus 

 communis, Sorbus aria, Cotoneaster vulgaris, etc., which are infested 

 with these galls. (2) Forms of the same type-species produce morpho- 

 logically different galls on the same or closely allied host-species. 

 They are sharply differentiated biologically, while their morphological 

 differences are imimportant. The author treats these as sub-species 

 on a trinomial system e.g., Eriophyes tiliae tiliae and E. tiliae typicus. 



Nalepa (A.). Neue Gallmilben (32. Fortsetzung). [New Gall Mites. 

 32nd Continuation.] — Anzeiger Kaiserl. Akad. Wissensch., Vienna, 

 liii, 1916, pp. 283-284. (Abstract in Zeitschr. f. Pflanzenkrank- 

 heiten, Stuttgart, xxviii, no. 1-2, 1st February 1918, p. 78.) 



Diptilomiopus javanicus, gen. et sp. n. (Phyllocoptinae), is 

 recorded in the galls of Eriophyes hemigraphidis, sp. n., on the leaves 

 of Hemigrap)his confinis in Java. 



