CECIDOMYIA. 73 



beautifully iridescent ; veins in their last subdivisions not more than six ; 

 costal vein extending nearly to the tip of the wing, or to the hind border ; 

 sudapical vein almost always obsolete. 



These flies are the most elegant and delicate little creatures in 

 the whole of the Diptera. The species are exceedingly numerous, 

 and generally of very minute size. Descriptions of the characters 

 and habits of all the British species would alone fill this volume, 

 but only a few of these have as yet been observed, and it is diffi- 

 cult to identify them with most of the published descriptions, and 

 I am not able to refer to collections for specimens of them. The 

 larvae are generally fleshy, oval grubs, rather attenuated in front, 

 and without any exserted appendages ; those of many species feed 

 on various parts of living plants, and are thus more or less in- 

 jurious to vegetation; some of them form galls, others feed on 

 decayed wood. The pupa resembles the imago, but its form is 

 much more contracted, with the wings and legs very short, and 

 resting upon the breast, in distinct cases. Winnertz has published 

 the most complete treatise on this family, and has reviewed the 

 works of nearly all the previous authors thereon. 



The genera may be grouped thus : 



C Distinct 1. CECIDOMYIA. 



Cubital vein \ 



(.Obsolete 2. LASIOPTERA. 



The only recorded genera in addition to these are Spcmwcera 

 and Heteropeza of Winnertz, and Brachineura and Ozirhynchm of 

 Eondani, which have not been discovered in Britain. 



Genus I. CECIDOMYIA. 



CECIDOMYIA, Latr. Gen. Cr. iv. 253 (1803); Meig. ; Mcq. ; Loew; 

 Winn. ; Zett. Tipula p., L. ; F.(Sp. I. et E. S.); Gmel.; D. G. ; Schr. 

 Chironomus p., F. (S. A.). Macrocera p., Meig. Kl. Cecidomyia et 

 Lasioptera p., F. (S. A.) Cecidomyza, Zett. Oligotrophus, Latr. 



Caput parvum. Oculi lunati, apud verticem contigui. Ocelli nulli. 

 Proboscis brevis, crassa. Palpi 4-articulati ; articulus primus brevis ; 

 secundus et tertius pleruraque sequales ; quartus ssepissime longior. 

 Antennas longae, 13-36-articulata3, moniliibrmes aut filiformes, ple- 

 rumque verticillato-pilosa3. Thorax rotundatus, nonuunquam gib- 

 bosus aut antice productus. Ala? ampla3, sa3pissime ciiiatas; vena 

 costalis alas apieem plerumque attingens; subcostalis apud cost.e 

 dimidium terminata ; cubitalis costali ad apieem connexa ; subapicalis 

 ssepissime nulla ; subanalis simplex, nonuunquam obsoleta ; analis 

 furcata, raro apieem versus obsoleta. Halteres magni. Abdomen 

 segmentis 8, plerumque lineare. Pedes saspissime lougi, graciles ; tibia3 

 non spinosae nee calcarata) ; metatarsus brevissimus. Mas. Antenna3 



VOL. IV. L 



