6o BRITISH GALLS 



severely taxed to demonstrate any identity of the organs of 

 the two instars." 



The antennae are of great importance in the classification 

 of Diptera. The majority of dipterous galls are caused by 

 the Cecidomyidae or gall- midges, an extensive family of 

 minute flies, remarkable in the rather long antennae, 

 furnished with whorls of hairs; many writers have com- 

 mented upon the beauty of these insects, and of the 

 antennae of the males in particular. The larvae of all 

 Cecids are not parasites on plants; some feed on dead 

 animal matter, others prey upon Aphides and Mites, and 

 some are caniiibals. 



The peculiar spatula or anchor process which projects 

 from the prothoracic seg;ment in some species is probably 

 used either for body movement, for perforating, or, in species 

 provided also with homy papillae at the terminal segment, 

 for causing the remarkable leaps executed by the larvae. 



The gall-midges are difficult to preserve, being so small 

 and fragile ; in spite of this they have received much 

 attention, and about a thousand species have been described 

 and named from various parts of the world. The original 

 genus, Cecidomyia, has undergone much revision of late years, 

 and has been split up into many genera, the chief being 

 Asphondylia, Contarinia, Hormomyia, OUgotropkus, Perrisia 

 (including many species at one time placed in the genus 

 Dasyneura), Rhabdophaga, and Rhopalomyia. 



Before proceeding to describe some familiar dipterous 

 galls, attention may be directed to certain curious pro- 

 ductions which have been recorded as occuring on fungi 

 on the Continent and in America. It seems desirable to 

 bring them to the notice of British cecidologists, as but 

 little is known respecting them at present. The first 

 observation was published by Professor Boudier* in 1893, 

 in a paper " Sur les Causes de Production des Tubercles 

 Pileux des Lames de Certains Agarics," in which he records 

 his discovery of minute oblong or rounded tubercles, about 

 * See Rev. Gin. Bot. (Paris), vol. v. , pp. 29-35. 



