TABANID^ 321 



apical spurs ; front coxjb rather long ; the legs very rarely exhibiting any dilatation 

 or structural ornamentation, but very frequently the front tarsi, and even tibiae near 

 their tip, bearing several " touch-hairs " on the underside. Pulvilli three, almost 

 equally pad-like. 



Wings with the normal fully developed venation of the Brachycera ; veins 

 usually all ending simple and entire in the wingmargin, except that the lower branch 

 of the postical fork meets or almost meets the anal vein before the wingmargin and 

 consequently the anal cell is always closed or almost so, and sometimes the first 

 and fourth posterior cells are also closed near the wingmargin ; radial vein long ; 

 cubital fork not long but very wide open, commencing well after the end of the 

 discal cell and with the upper branch ending well before but the lower branch 

 far after the wing-tip ; discal cell near the middle of the wing, long and 

 hexagonal, and emitting three usually simple veinlets to the wingmargin, though the 

 upper one may be sometimes united to the lower branch of the cubital fork a little 

 before the wingmargin, and the lower one sometimes united to the upper branch of the 

 postical vein also near the wingmargin so that the first and fourth posterior cells or 

 one of them may become closed ; the upper branch of the cubital fork often emits 

 a short recurrent veinlet ; the lower branch of the cubital fork always ends much 

 nearer to the end of the first veinlet from the discal cell than to the upper branch of 

 the cubital fork ; discal and small cross-veins quite distinct at about the basal 

 quarter of the discal cell, and consequently there are five well-distinguished posterior 

 cells ; basal cells long and e(|ual in length ; ambient vein entire, encompassing the 

 whole hindmargin of the wing ; alula strongly developed though not very large ; 

 wing-membrane conspicuously ripj^led, and very densely but very minutely 

 pubescent. Alar squama3 moderate in size or rather large and having folds, very 

 short fringed on the usually dark margin but with a long and shaggy tuft at the 

 angle ; thoracal squamiB strongly developed and rather upraised, lying close against 

 the angle of the frenum, and bearing a short fringe. Halteres not much concealed 

 by the squamte. 



The Tabanidce form one of the most easily distinguished families of 

 the Eremogh^ta, as the annulated third joint of the antennae is only shared 

 in the Palsearctic region by the very distinct Stratiomyidm and by a few 

 aberrant Le^jtidce. From any Lcptidce they are at once distinguished by the 

 strongly developed raised thoracal squama3, by their broad flat shape, 

 very distinct wide-mouthed cubital fork, and the blood-sucking habits of the 

 females. From the Stratiomyidce they are almost always distinguished by 

 the large thoracal squamse, and in any Stratiomyidce when these squamse 

 are well developed they are of a very different texture and have woolly 

 surfaces, while at the same time the ambient vein is entirely absent and 

 the anterior veins are all crowded together on the foremargin of the wing. 

 The only other family of the EiiEMOCHiETA with large thoracal squamse is 

 the Cyrtidoe, and their globular hump-backed figure, diminutive head, and 

 balloon-like abdomen at once differentiate them in a most striking 

 manner. 



The Tabanidce are composed of the well-known biting " Horse-Flies," 

 and are distributed over the whole world. About 1600 species are known, 

 of which nearly 200 are Palaearctic and about 200 North American. 

 Many of the species are conspicuous from their large size and none are 

 small. The females are persistent blood-suckers and are always ready to 

 attack man as well as animals, but the males are much more rarely met 

 with and may be seen resting on tree-trunks, palings, etc., or on flower 

 blossoms, though Osten Sacken states that they hover in the air on 

 mountain-tops at sunrise, and Schiner says that the males of IIcBmato])ota 



X 



