Messrs. Baguall and Harrison's British Cecidomyidae. 347 



importance in biology as suitable subjects for studying the 

 early segregation of germ-cells. 



There is no excuse for our naturalists to continue this 

 systematic neglect of the group. Houard (1908-1913) 

 includes descriptions of all the then-known Cecidomyid 

 galls of the western section of the Palaearctic area in his 

 great work on the Zoocecidia. Furthermore, there has 

 been in recent years a steady flow of literature as the 

 result of the researches of continental entomologists such 

 as Kieffer, Trotter, Tavares and Riibsaamen. The first- 

 named author's monograph in Wytsman's " Genera 

 Insectorum " (fasc. 152), which appeared in 1913, will, 

 with the fine productions of Dr. Felt, in America, form 

 the groundwork of much further work. Lastly, an 

 Italian periodical, " Marcellia," edited by Prof. Trotter, 

 keeps one up to date with new researches. 



It will thus be seen that in the Cecidomyidae we have a 

 group not only displaying abundant and varied interest in 

 its biology, but one provided with a literature unusually 

 rich for a " neglected order." 



During the past three seasons we have devoted much 

 of our leisure in this fascinating study and with consider- 

 able success. We have therefore been tempted to publish 

 the present list as a record of our labours and as a basis 

 for future work and workers! We have included references 

 to («) original descriptions of genera and species, (6)Kieft"er's 

 1913 Monograph, and (c) to Swanton and Houard as far 

 as Gall-midges are concerned, quoting only the authors' 

 numbering of the gall. In addition we have appended 

 an index to the host-plants. Owing to the fact that 

 Connold's works on galls are very far from complete, and 

 also because Swanton supersedes them, we have not 

 deemed it necessary to refer to that author. 



Soon we hope to prepare a book on British Zoocecidia, 

 and later, when we have bred out and studied, as far as 

 our limitations will allow, the hfe histories of the insects, 

 we shall, in all probability, proceed with a more elaborate 

 monograph of the Cecidomyids. It is, then, for these 

 reasons that we characterise this as a " preliminary " list. 



The species noted from the north of England, e. g. from 

 the counties of Northumberland, Durham, Cumberland, 

 Westmoreland, Lancashire, Cheshire and Yorkshire, are 

 shown in heavy type. Species not yet reported from that 

 area are shown in italics, whilst those ascribed to older 



