12 H. C. EFFLATOUN. 



longitudinal lines. It very often bears a distinct soft pubescenœ 

 ^\llicll inay eitlier be very slight and inconspicuous, or quite long, 

 close and dense, but which hardly ever bears any bristles or bristly 

 Imirs. Scuttellum usually resembling the thorax in colour and 

 pubescence and sometimes bearing bristly hairs on its inargin which 

 ])rovide important spécifie characters. 



Abdomen varying very rauch in shape and colour and com- 

 posed of five or six visible segments and never bearing any bristly 

 hairs. Hypopygium nearly ahvays asymmetrical and usually net 

 prominent; the abdomen is generally thinly pilose or bare, but some- 

 times clothed with dense pile or dust or both. 



Legs usually moderately strong, but varying very much in 

 shape and pubescence and when bristles are présent they are found 

 only ou the under surface of the femora. The females of ail species 

 hâve the legs reduced to a very simple form. Sometimes the tibiae 

 and the apioesof the tarsal joints bear small apical spurs and occa- 

 sionally the hind troehanters and femora are armed beneath, 

 especially in the maie, and thèse afford valuable characters for 

 distinguishing species. 



Wings comparatively large and with a specialised and distinct- 

 ive venation. Radius 4 + 5 never forked; Media 1 + 2 terminâtes 

 in Radius 4 + 5 well before or near the tip; Cell RI either opened 

 or closed; basai cells large and well distinguished; cell Al elongated 

 and always closed before the border of the wing. Running right 

 across the radio-median cross-vein, between Radius 4 + 5 and Media 

 1 and almost parallel with them, the vena spuria or false vein is 

 aoarly always présent. Although this false vein is characteristic 

 of the family so that its présence certainly secures the admission 

 iiï any species to this family, its absence does not exclude a 

 species, as it often exists in a very faint or almost imperceptible 

 form. Alulae always distinct and nearly always well developcd. 

 Squamulae small or fairly large with a distinctly thickened 

 mai-gin and almost always with délicate fringes which may be 

 composée! of sim])le or comjiound hairs. Jlaitc>res usually moderato 

 in sizo. 



The Syrphidac foi'm onc of the largest, most shar])ly definod, 

 find best known of ail the faïuilies of Diptera. Thei-c are over 

 2500 specirs known throughout the world. They occur in ail 

 régions froni the Tropics to the Pôles. They contain among them 

 many of the brightest coloured Aies and in the sunlight are 

 remarkably good hoverers and usually very active fliers. The adults 

 are almost always attracted by flowers, especially Co?npositœ, 

 Umbelliferae and Rosaceae. Some species fly in and out about low 

 herbage and flowers and others may be seen resting on leaves and 



