BRITISH FLIES 



I would therefore give the following characters for the two great 

 divisions of the Orthorrhapha : — 



NEMOCEEA. 



Palin pendulous, generally four- or five-jointed and more or less fili- 

 form ; when, as in Aedcs and some genera of Cecidomyidcc, there are only 

 one or two joints, the structure of the antennoe and the venation remove 

 all douhts. 



Antenna; always with a many-jointed Jlagellum after the two basal 

 joints, and this flagellnm always comjjosed of a number of joints (G-39) of 

 which the majority are similar to each other ; these joints usually resemble 

 a string of beads or rings not necessarily all equal in length or pubescence, 

 and some of the joints of the flagellnm are frequently verticillate, as in 

 Cecidomyidce (fig. 1), or verticillate plumose, as in Chironomus (fig. 3), or 

 rarely pectinate, as in Cfenophora (fig. 5), and sometimes remarkably 



Fm. I.— Per nsu( veronicce <J. x 42. 



Fin. 2. — Perntiia veronicce. 9. x 42. 



elongate, as in Macrocera (fig. 7), and the joints almost always differ in 

 ornamentation and lumiber in the sexes, as mav be seen in the female of 



Fic. 3.—Chironoinvs S- x 22. 



Fia. 4.—Chirono-mus <i . x 31. 



Cecidomyia (fig. 2), or Chironomiis (fig. 4), or Ctenophora (fig. 6) ; sometimes 

 the flagellnm is merely composed of a series of rings rather closely crowded 



