comparative Chcetotaxy. 505 



how far it was applicable to the other great divisions of 

 Diptera. I found that the homologies were so sti-H inJ 



j-rt/peuacB) but at the end of this paper a brief skefr^h 



gv n '^t'Sch'-'"^ ^"'"^•?'^^ ''''''' ^^^ 

 not exhaustive ,. ^necessarily approximative, and 



hvll+il ^ ^ '. "^'^""^ ^*^^®i" characteristic hairs and 



2.— It must be borne in mind that, in enumeratinfr flip 

 lateral bristles of the head or thoi4x, onHide onlv ! 



mStS^^^tet"'^^^' ^^^. V"^^^tatbi-sL^^ 

 means tnat theie are two on each s de of the head On 



he contrary, the bristles on the central portions of the 

 head or thorax are enumerated in pairs. Tir vertical 

 bristles, one inner and one outer plir, means th^tW 

 are two vertical bristles on each sid^ one of w ich 

 belongs to the inner, the other to the outer pai? 



3.- The abdominal bristles do not require anv special 

 terminology; heir position is easily defined bfnam n. 

 the abdommal segment on which they are inserted 

 Only the margmal bristles maybe diswiLhed from 

 the discal as Eondani has done it (Prodr ^h n 244? 



Vienna 187S^n q T^^^^f ° ^gj^che Untersuchungen,' 

 Vienna, 1878, p 3, note) should be followed :—" On the 

 legs I distmguish a front and hind side, and uppei and 

 under side When a leg is stretched out Lrtzontahv 

 and perpendicularly to the longitudinal axis of tie bod v 

 he ront side is that which is turned towards the head 

 the hmd side that which looks towards the anus the 



comse. I call prasapical bristles those which occur 

 principally on the front side of the hind femorfof many 

 fohchopoduke, singe, elongated, erect bristles.'' The 

 same term of pr^apical bristle was used by Dr. Schiner 

 for a characteristic bristle at the end of the tib '^ hisime 

 ^m^^,r«i« (especially Sciomy.id^). Thus the forrer 

 won Id be the femoral, the latter the tibial prJ:;": 



