2. TABANUS 359 



Iialf-way up the segment; the bhicker hue of the abdomen makes the 

 side tufts of whitish pubescence at the hind corners of the segments more 

 conspicuous. Belly usually unicolorous blackish grey without any trace 

 of ferruginous coloring. 



This species, like most of the genus, requires care in identification, but 

 may often be known in the large strong specimens by the considerable 

 amcimt of blackening on the apical half of the hind tibiae (though I distrust 

 this character), and by the posterior tarsi being less ferruginous at the 

 base than in any of the succeeding species ; both sexes may be distin- 

 guished from T. sohtitialis and T. distingucndus by the absence of the 

 conspicuous bright orange abdominal coloring; from T. montanus by the 

 larger size, by the tuft of black hairs on the vertex, and by the more 

 pubescent middle tibiae ; from T. luriclus in both sexes by the normally 

 larger size, and in the male by the less blackish ground colour and by the 

 longer extent of the touching of the eyes, while the female has no sign of 

 any shining black frontal triangle. T. horcalis is not well known to me, 

 but it should have larger front eye-facets in the male and a broader frons 

 in the female, while I believe both sexes have more conspicuous whitish 

 hindmargins to the abdominal segments. 2\ tropicus varies in many respects, 

 and I have notes that the male may have the outer part of the jowls near 

 the mouth black haired, the pubescence on the palpi mainly pale but 

 with numerous black hairs on the front part and some long ones about the 

 tij) of the basal joint, piibescence on the belly much paler as the black hairs 

 are almost limited to the middle of the sixth segment though still 

 conspicuous on the seventh segment, colour of the belly very much more 

 obscured as there are only some obscure yellowish brown markings on the 

 second, third, and fourth segments; it also varies in size, l)ut is always 

 larger than T. montanus and T. luridus. One specimen (when seen from 

 behind), is even more light greyish on the abdomen so that the light grey 

 coloring occupies most of the second and third segments and forms faint 

 traces of side-flecks on the fourth and fifth segments. The female varies 

 (besides the melanochroitic variety bisignatus) in a specimen taken at 

 Worcester on July 3, 1869 (which was returned by Brauer and referred to 

 by him in his monograph as typical T. tropicus) in having the thorax 

 narrower and less black, the abdomen narrower and more oblong with the 

 brownish red coloring more extended and more sharply defined on the 

 inner margin to the end of the third segment and altogether more orange 

 red and less blackened towards the sides of the second segment when 

 seen from above, middle tibiae not so pubescent, frontal triangle 

 apparently less broad, tuft of black vertical hairs less obvious. A still 

 more remarkable female is one which was taken by Colonel Yerbury at 

 Clifford's Castle in Herefordshire on August 13, 1902; some of its 

 peculiarities are probably due to immaturity, but it is so small (12 mm.) 

 that I could not for a long time associate it with T. tropicus though I 

 have ultimately come to the opinion that it must belong to that species ; the 

 long dense pale brownish grey pubescence on the eyes, the brownish grey 

 frontal stripe on which the pubescence is long and black, the very obvious 

 tuft of black vertical bristles, and the small grey triangles on the dorsal 

 line of the abdomen are characters exactly agreeing with 2\ tropicus and 

 very different from T. uionfanus ; the frontal stripe is narrower and 

 parallel-sided on the upper half and has the black pubescence on this part 



