BRITISH GALL-GNATS. 147 
however, difficult, and the specific characteristics very superficial. 
It is this which makes a knowledge of their economy so im- 
portant, and in the case of many species it is most interesting. 
The Cecidomyide have had a double band of students; the 
abnormal vegetal productions, which many of them occasion, 
have attracted the attention of many botanists, as well as 
entomologists ; while but few have turned their attention to the 
insignificant gall-makers themselves. 
Both must go hand in hand. J. J. Bremi, of Zurich, was the 
creat pioneer in this direction (1847), and he was soon followed 
by H. Loew (1850) and Winnertz (1853). Bremi’s valuable 
memoir, published in volume nine of the ‘ Neue Denkschriften 
der alle. Schweizerischen Gesellschaft,’ is illustrated with two 
excellent coloured plates, containing admirable figures of twenty- 
seven distinct galls, together with various details of certain 
imagos. H. Loew’s Dipterologische Beitrage, No. 4, was pub- 
lished in the ‘Programm des Konigl. Friedrich-Wilhelm- 
Gymnasiums zu Posen,’ and was followed in the succeeding year 
by a paper, ‘ Zur Kenntniss der Gallmucken,’ in Linnea En- 
tomologica (vol. v., pp. 870—384). Winnertz’ important ‘“‘ Mono- 
eraphie der Gallmucken”’’ was also published in Linnea 
Entomologica (vol. vii., pp. 154—824); this is illustrated with 
four plain plates, mostly containing details, especially antenne, 
palpi, wings and ovipositors, of the imagos. Several of these 
enats and their galls came under the notice of the older authors, 
notably Réaumur, Frisch, Swammerdam, DeGeer, and Schrank, 
but it is with Meigen that the real history of all Diptera com- 
mences. The first volume of his wonderful work was published 
in 1818. This contained the Cecidomyide ; in the whole work 
Meigen has described fifty-two species, but the identity of several 
is quite uncertain. 
Further reference to gall-gnat literature cannot be made 
here. I only need say that Dr. Franz Low is now studying the 
Cecidomyide and their productions, and his papers have lately 
been published in the ‘ Verhandlungen z.-b. Gesellschaft in Wien.’ 
Volume twenty-six of this publication contains the ‘‘ Synopsis 
Cecidomyidarum,” by J. E. v. Bergenstamm and Paul Low, of 
which I have made great use in preparing the accompanying 
table of our British species. 
Rondani’s division of the family Cecidomyide into the two 
