86 Orthorrhapha braclivcera. 



niandibles are waiitiny:. Tho maxillary palpi are large. Iwo-jointed ; 

 in the male porrect and with the second joint often short and 

 thickened, in the female pendulous along the front side of the rostruni 

 and with the second joint often longer, more or less curved, and 

 pointed. As the moutli parts are connected witli the mouth-edge of 

 the head by a short connecling membrane. the proboscis is thus only 

 .sliglitly pro- and retractile. Thorax nearly quadratic or rectangular; 

 scutellum without spines. Abdonien consists of seven not transformed 

 segments. Legs of middle length, without bristles, the front coxæ some- 

 what lengthened, the posterior coxæ short ; the posterior tibiæ, or the 

 middle tibiæ alone, with two apical spurs; tarsi with simple claws: 

 two pulvilli and a pulvilliforni empodinm, being quite uniform with 

 the pulvilli. Most of the Tabanids show a cui-ious structure on the 

 front femora; while the femora otherwise are clothed with hairs and 

 often pruinose. the front femora are shining and glabrous beneath and 

 witiiout liairs, and they show a fine, transverse striation; the .signi- 

 ficance of this structure I do not know, but I shall in this connection 

 call attention to the faet. that the front tarsi of the Tabanids nearly 

 always show a biack coioration, that is only rarely the case with the 

 posterior tarsi. When species of Tabanus are held in captivity. they 

 are seen to use the front legs in a palpating nianner. The above 

 mentioned structure of the front femora I have observed in Chnjsops, 

 Silvius, Hexatoma, Tabanus and Dichelacera but nol in Paugonia or 

 Hceniatopota ; thus it would seem. tliat the groups PaugoHiiuæ and 

 Tabaninæ are not very natural, as already noticed by Hansen (Nat. 

 Tidsskr. 3, XIV, 93). Wings with the costal vein extending all round the 

 margin: the discai cell fornied exclusively of the discai vein; the cubital 

 vein forked, the upper branch sometimes with a recurrent veinlet: 

 two cubital and five posterior cells; the discai cell nearly in the middle 

 of the wing; the basal cells of equal length; the anal cell extending 

 nearly to the margin. The squamulæ of equal or nearly equal size, 

 (lislinct, but not covering the balteres, finely fringed along the margin, 

 at the angulus long haired; alula distinct. 



The eggs are deposited on plants in the water or in more or less 

 humid localities. The larvæ are cylindrical, pointed towards the ends 

 and finely striated longitudinally. They are metapneustic (or am- 

 phipneustic. Hæmatopota?) with a terminal vertical split leading to the 

 spiracles. The head and the terminal segment are retractile. The 

 body consists of twelve segments, including the head; it has, on most 

 of the segments, swellings with fine spines. The mouth parts consist 

 of a median vertical labrum, hookformed niandibles and maxillæ, the 

 latter with two-jointed palpi : niandibles and maxillæ are moved vertically. 



