370 TABANID.E 



ground colour (occupying only about one-fifth the length of the segment). 

 Pubescence pale grey (as mentioned before) on the side-flecks on the second 

 and third segments and on the small dorsal triangles, and also on the sides of 

 the hindmargins from the second segment onwards, while the pubescence on 

 the sides of the two basal segments is rather dense and pale but not very short, 

 and that on the other parts of the abdomen is very short, sloping and 

 black, though slight indications of side-flecks on the fourth and fifth segments 

 are caused by scattered pale hairs on those parts. Belly greyer than in the 

 male and with the ferruginous part restricted to parts of the outer thirds of 

 the second segment and most of the third segment except the sides and 

 middle of hindmargin, though in dark specimens scarcely any ferruginous 

 coloring exists ; pubescence ubiquitous and rather conspicuous, pale and 

 sloping, and with scarcely any trace of erect black hairs on the last segment. 



Legs dull black, but the tibiee conspicuously orange-red except at just the 

 tij) of the posterior pairs and on about the apical half of the front pair, posterior 

 tarsi more reddish orange at the base and the middle pair extensively so on 

 the underside. Pubescence on the front femora abundant and mostly black, 

 but on the posterior femora nearly all conspicuously greyish white though 

 black about the base of the middle pair ; posterior tibiae with much shorter 

 and less conspicuous pubescence than in the male, though the coarse black 

 dorsal ciliation on the hind tibiae is conspicuous. 



Wings, squamae, and halteres as in the male. 



Length about 13 mm. 



This species varies but little in the male beyond what has been 

 mentioned in the description, but there is occasionally a slight trace of 

 reddish orange on the fourth abdominal segment adjoining the spot on the 

 third segment near its inner margin ; while the variation in the amount 

 of reddish marking on the abdomen of the female is considerable but has 

 been also given in the description. It is an easily recognised species in 

 the female as it may be immediately distinguished from all its allies by 

 the shining black frontal triangle as well as by numerous other characters, 

 such as the broader more hairy frontal stripe, the longer darker haired 

 eyes, the larger longer haired basal antennal joint, the less drooping 

 less tapering and less black-bristled palpi, etc., but the male requires 

 closer examination as at first glance it resembles T. montanus. The 

 male of T. montaniis has longer and more pointed palpi, smaller basal joint 

 of the antennae which bears much shorter hairs, eyes with shorter paler 

 pubescence and less equal facets and actually touching for a much longer 

 space, duller thorax and abdomen, browner posthumeral calli, much 

 narrower black dorsal stripe on the abdomen, and usually more extended 

 reddish coloring on the first and fourth segments and the dorsal grey 

 spots broader, legs with paler less pubescent tibiae and paler haired femora, 

 and wings without any clouded cross-veins. N"o other continental species 

 can be confounded with the female. Both sexes are easily known from 

 their allies by their brightly shining appearance. 



T. hiridus was first recorded with certainty as British from a number 

 of females taken by Colonel Yerbury at Nethy Bridge in Inverness in 

 June 1900, and it was again taken by him in considerable numbers in 

 June and July 1905 at both ISTethy Bridge and Brodie, while on June 9 and 

 10 he took four males at Brodie. His dates range from June 5 to July 1, 

 though in writing to Mr Austen he said, " In May 1905 it was met with 

 " in numbers near Nairn, when both sexes were found sitting on a sandy 

 " road leading to Maviston Sand Hills," and he states that it appears to be 

 an earlier species than T. montanus. Previous records exist but probably 

 refer to some other species, though Duncan's record (1837) of " Sutherland- 



