10 BRITISH FLIES 



characteristic bristles (fig. 33), and at the same time the legs Lear small 

 spicules, or even bristly spines on the femora, which are quite distinct 



from any structural serration, and the first 

 (j.i^^^l-^i::^:;;;^^-'-''' — indications occur of an apical circlet of 



/^■- -^^y^ ^^ spurs or spines on the tibi;o; the Derma- 



Xy'^—-^.,^ TINA {JirpMO'ianidm and Myclmdce) axet oi a 



•"YJ ^ more coriaceous nature and, though not 



V_ji.„ ^Voer^"^^^^^^^^ truly chsetophorous, begin in some species 



V vWw|p)^^ l^ of Mydaklm to exhil;)it small spines (not 



^^-^^^^-^f vK"^^^- spicules) on the tibite besides a rather 



til M \ bristly serration Ijeneath the hind femora ; 



"^"^M^.^J the ExERGOPODA (Apioceridcfj and Asilida:) 



VM.33.-The,-evanubtiucda <i. x 10. and tlic MiCROPHONA {Emindd', DoHchiypo- 



didce) and subsequent families l)ear distinct 

 macrocluetffi on head, thorax, and legs (unless they are replaced, as in 

 some A.silidcc, by dense coarse pubescence). 



In all cases of doubt as to whether a fly belongs to the Braohycera 

 or the Nemocera (and doubt could only arise in some Stra Homy idee and 

 Leptidce) because of an annulated flagelluui-like third joint of the antennte 

 (as in lihachicerus, Beris, Xylojjhagiis, Co&nomyia, etc.), the contraction of 

 the anal cell towards the wingmargin provides an infallible character. 



Brauer gives the following characters for distinguishing the larvcC of 

 the Brachycera from those of the Nemocera :— 



" LarvcB with parallel upwards and downwards or outwards and down- 

 " wards grinding jaws, which act in piercing, hacking, boring, or sucking. 

 " Head not fully developed, only a jaw-case without ganglia present, which, 

 " however, sometimes is almost a head because of the outwardly i)ro- 

 " jecting eyes. — Chain of ganglia beginning behind the jaw piece. — Larvae 

 " with rudimentary mouth-parts, mota- or amphi-pneustic, and composed of 

 " 10-12 segments." 



THE DIl'TEKA OETHOKRHAPHA BKACHYCEKA 



may be divided into sixteen families, which have been associated into 

 groups or superfamilies in various ways. 



The exact boundary line between the Orthorrhapha and the Cyclor- 

 RHAPHA is still rather uncertain, and one of the last students of this 

 subject (de Meijere, Zool. Jahrb., xiv., pp, 87-132, 1900) is of opinion that 

 the Lonchopteridce and Fhoridce should commence the Cyclorrhapha 

 rather than close the Orthorrhapha. Osten Sacken's final views (1902) 

 were that the Phoridce were true Orthorrhapha, but that they had no 

 "real affinity" with any other family. My own studies have not suffici- 

 ently included these difficult questions, and consequently I am unable to 

 give any strong opinion, except to say that I believe the Phoridce to have 

 their nearest "affinity" in the Loncliopteridce, and the Lonchopteridce in 

 the Dolicliopodiduc. 



