218 PROF. M. BEZZI. 



27(20). Basal segment of the costa provided with two groups of strong spines 

 before the costal bristle . . . . . . . . Bistrispinaria, Speis. 



28(17). No distinct middle scp. ; legs long and slender ; wings long and narrow, 

 with the small cross-vein much before the middle of the discoidal cell 

 and adorned with yellowish longitudinal rays ; head " balanced," with 

 narrow eyes and strongly developed lower occipital swellings 



Xanihorrhachista, Hend., p. 241. 



29(12). Dc. placed much behind the line of the a. sa., and therefore very far from 

 the suture ; eyes usually rounded ; lower occipital swellings absent or 

 less developed ; hind cross- vein outwardly oblique. 



30(33). Second longitudinal vein distinctly wavy ; scutellum with three pairs of 

 bristles, the intermediate pair being however often much smaller than 

 the others ; arista usually plumose or pilose. 



31(32). St. wanting ; head much broader than the thorax ; middle scutellar 

 bristles weaker ; 3rd and 4th longitudinal veins with their last portions 

 parallel . . . . . . . . . . Themarictem, Hend., p. 243. 



32(31). St. present ; head not or a little broader than the thorax ; middle scutellar 

 bristle as strong as the others ; the above-named veins diverging 

 distally ; arista plumose or pubescent . . . . Themara, Walk., p. 244. 



33(30). Second longitudinal vein straight. 



34(37). Scutellum with three pairs of bristles ; third longitudinal vein with 

 numerous and very long bristles on its whole length. 



35(36). Head normal, with rounded eyes ; i. or. present ; antennae separated 

 by a keel from the base ; lower angle of the anal cell drawn out in a long 

 point . . . . . . . . . . Baryglossa, gen. nov., p. 244. 



36(35). Head abnormal, with very narrow eyes ; i. or. wanting ; no keel between 

 the antennae ; anal cell not produced below . . Cladoderris, Bezzi., p. 246. 



37(34). Scutellum with only two pairs of bristles. 



38(39). Arista plumose ; oc. rudimentary or wanting ; wings mostly black 



Ptiloniola, Hend., p. 246. 

 39(38). Arista bare or shortly pubescent. 

 40(41). Face very concave, without a distinct middle keel, but with prominent 



sides ; abdomen long and thin, rather conical 



Coelopacidia, End., p. 248. 

 41(40). Face of usual shape, with more or less distinct middle keel ; abdomen ovate, 



not conical. 

 42(43). No prst. and no oc. ; wings with the small cross-vein placed near the middle 



of the discoidal cell and with the last portion of the 4th longitudinal 



vein curved and diverging from the 3rd Rhacochlaena, Loew, p. 248. 



43(42). Prst. always present ; oc. usually well developed ; last portion of 4th vein 

 not or less curved and not or little diverging. 



44(45). Small cross-vein near or before the middle of the discoidal cell ; wings 

 adorned with narrow, vertical, fuscous bands, which are often partly 

 bioken into spots . . . . . . . . . . Phorellia, K.D., p. 249. 



