1914] CURRENT LITERATURE 95 



mycelium spreading from old knots; the fungus during the first year penetrates 

 nearer to the pith in the distal than the proximal end, and the greatest dis- 

 turbance is in the vicinity of the leaf gaps; in the case of the choke cherry, which 

 was the host used in these studies, the multiseriate rays become broadened, 

 the production of xylem elements is greatly inhibited, and the production of 

 parenchyma stimulated. There is also a stimulation of the cambium accom- 

 panied by the misplacing of certain elements. The reviewer will add that 

 many of the data given in this paper are homologous with those derived from 

 the study of insect cecidia. The American botanical literature is very deficient 

 in studies of pathological tissues, and it is to be hoped that this paper will 

 stimulate research in this long-neglected field. 



Cosens 15 gives a paper which is very suggestive to botanists, in which he 

 says: "One fundamental and far-reaching principle of gall-production by 

 insects is that the stimulus does not endow the protoplasm of the host with 

 power to produce new types of organs, tissues, etc. Structures are in many 

 cases originated that are not found on the same part of the normal host, but 

 invariably their prototypes are present on another part of the plant or nearly 

 related species. The protoplasm is so stimulated that not only are dormant 

 characteristics strengthened, but also in certain cases latent properties are 

 called into activity, and thus the apparently new type of production appears 

 in the host." The author gives evidence from the study of several galls 

 supporting this principle. 



Among other American papers which should be mentioned is a valuable 

 key for determination of the midge galls on the hickory by Felt; 16 and a • 

 very interesting biological paper by the same author 17 on adaptations; and 

 also several systematic papers by the same author. 18 There should also be 

 noted three valuable taxonomic papers by Beutenmuller on the acorn galls 19 

 and on new species of the Cynipideae. 20 — Mel T. Cook. 



[i 



x * Cosexs, A., Insect galls. Canad. Ent. 45:380-384. 1913. 



16 Felt, E. P., Table of hickory leaf midge galls. Bull. Brooklyn Ent. Soc. 

 8:98-99. 1913. 



17 , Adaptation in gall midges. Canad. Ent. 45 •' 3 71-3 79- x 9 r 3- 



, Three new gall midges. Canad. Ent. 45:305-308. 1913. 

 , Description of gall midges. Jour. X.Y. Ent. Soc. 21:213-219. 1913. 

 , Gall midges in an aquatic or semi-aquatic environment. Jour. N.Y. 

 Ent. Soc. 21:62, 63. 1913. 



, The gall midge fauna of New England. Psyche 20: 133-146. 1913. 



19 Beutenmuller, William, The North American acorn galls with descriptions 

 of new species. Bull. Brooklyn Ent. Soc. 8:101-105. 1913. 



20 



282. 1913. 



, A new species of Neuroteras from Washington. Canad. Ent. 45:280- 



, Descriptions of new Cynipidae. Trans. Amcr. Ent. Soc. 39:243-248. 



1913. 



