CECIDOMYIA. 73 



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

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

 subopical vein almost always obsolete. 



These flies are the most elegant and delicate little creatures iu 

 the whole of the Dijdera. The species are exceedingly uuinerous, 

 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 

 1 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. A\'iunertz 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 : — 



r Distinct 1. Cecidomyia. 



Cubital vein < 



(.Obsolete 2. Lasiopteua. 



The only recorded genera in addition to these are Sjyaniocera 

 and Helero2)eza of Winnertz, and Brachlneiira and Ozirhpichus of 

 liondani, wdiich have not been discovered in Britain. 



Genus 1. CECIDOM'^IA. 



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

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

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

 Lasioplera p., F. (S. A.) Cecidomyza, Zett. Oliyolrophus, Latr. 



Caput parvuin. Oeuli liniati, apud verticem contigui. Ocelli nulli. 

 Proboscis brevis, crassa. Palpi rt-avticulati ; articulus prinms brevis ; 

 secundus et tcrtius plcriimque a^qualcs ; quartus snepissinie longior. 

 Antenna} longi.c, 13-3G-articulata', nioniUtbrmes aut filifonnes, ple- 

 rauKpie verticillato-pilosse. Thorax rotundatus, nonnunquam gil)- 

 bosus aut antice productus. Ala) ampUie, stcpissimc eihata) ; vena 

 costaHs alte apiecm pleruraque attingens ; subeostalis apud coslic 

 diinidiura tenninata ; cubilalis costali ad apicem connexa ; subapicalis 

 SBepissime nulla ; sul)analis simplex, nonnunquam obsoleta ; aiialis 

 furcata, rare apicem versus obsoleta. Halteres magni. Abdouieu 

 seginentis 8, plcrmnriue lineare. Pedes sa-pissime longi, graeiles ; tibias 

 non spinosa? nee calcarata3 ; metatarsus brcvissimus. Mas. Antenna; 



VOL. IV. 1 



