INTUODUCTION. XXXI 



ORTHORRHAPHA. 



Nemoceva vera. No lioloptic head in the male sex ; no bisection or bicol- 

 oration of tlie eyes. Antennas provided with sensitive hairs ar- 

 ranged symmetrically on the flagellum in verticils or pencils of 

 hairs (exception Mycetophilidas). No ocelli (exception Mycctophi- 

 lida^ and Lestreminie). No pulvilli; empodia often but not always 

 present. 



A. Larvaj peripneustic*, always terrestrial. Families Cecidomyidaj, 



Mycetophilidae. 



B. Larvffi metapneustic oramphipneustic, aquatic, subaquatic, sometimes 



terrestrial. Families, Culicida?, Cliiroiiomida^ Psychodida^ {'.) 



IS/eiitocera anomala. Diptera with— l+©«mtegw»s joints to the flagellum, Q 



usually four-jointed palpi. Males frequently holoptic, sometimes tyV^ly 



the females also. Pulvilli usually present. Antennje without sensi- 

 tive hairs. Ocelli usually present. Families Bibionidse, Simuliida\ 

 Blepharoceridse, Rhyphidae, Orphnephilidfe. 



Brachjicera. Palpi one or two-jointed, not pendulous, porrect, the second 

 joint more or less clavate, larger than the first. Joints of the flagel- 

 lum usually not homologous. 



No macrocluctffi. Three well developed pulvilli. Males predominenth' 

 holoptic, the eyes often bisected. Antennal flagellum polymorphous. 

 Axillary incision, alula ami antitcgula in most cases distinctly devel- 

 oped. Discal cell usually present; usually five posterior cells. 

 Legs rather smooth. Families Stratiomyida?, Tabanidai, Acantho- 

 nieridaj, Le])tida;. ....... Ekemochjeta. 



Collection and Preservation of Diptera. 



Flies must be collected with much more care than can be 

 safely used with such insects as coleoptera. Moisture of all 

 kinds injures or ruins them, and specimens collected in alcohol 

 are worthless. For this reason the collecting bottle should be 

 lined throughout with blotting paper, and the cyanide placed 

 in the cork ; a very little poison suffices to kill them. Nor 

 should they be allowed to become too dry before pinning. 

 Tlie i)in should be thrust through the middle of the thorax, 

 and the specimen placed just so as to enable the head of the 

 pin to be grasped by the thumb and finger safely. Very small 



* Amjihipnenstic larva; are those in which the s])iracles are confined to the 

 first and last segments; vK'tajmeustir those in whicdi they are (confined to tiie 

 posterior segments; pfrijutciistic those in which they are abaewt on the 

 median rings. hAtJj^vTC 



