SOME SIAMESE TABANIDAE. 439 



but not produced. Thorax : Dorsum — except fore border, scutellum, humeral and 

 post-alar calli, swelling occupying depression at each end of transverse suture, a 

 small area in front of suture immediately above each of these swellings, and extreme 

 hind margin of scutum — blackish-brown, and clothed with similarly coloured hair ; 

 anterior surface and fore border of dorsum smoke-grey or light greyish-olive pollinose, 

 the pollinose area extending on each side to transverse suture, and clothed with 

 appressed, glistening yellowish hair ; swelling in depression at each end of transverse 

 suture, and area immediately above it in front of suture, pinkish-buff or cinnamon- 

 buff, covered with olive-buff pollen and clothed with longer bright yellowish or ochreous 

 hair, swellings at ends of suture also with a certain number of black or blackish hairs 

 below ; humeral and post-alar calli, and extreme hind margin of scutum pale smoke- 

 grey pollinose, and clothed with 3'ellowish hair ; pectus agreeing with pleurae in 

 coloration and hairy covering. Abdomen: First and second (visible) tergites mainly 

 chestnut-brown, remainder of dorsum, except as already or subsequently described, 

 black or blackish-brown ; first (visible) tergite blackish-brown in centre ; second 

 tergite with a, not sharply defined, median triangular patch and a blotch on each side 

 (not extending into posterior angle) of same colour ; lateral extremities of first (visible) 

 tergite, and posterior angles of second tergite, olive-buff pollinose and clothed with 

 yellowish hair ; hind margins of fifth and sixth tergites (sometimes that of seventh 

 tergite also) narrowl}^ olive-buff pollinose, and clothed, at least in part, with hair of 

 same kind as that on hind borders of third and fourth tergites ; dorsum, except as 

 stated, clothed with short appressed black hair ; venter at base, as far as hind margin 

 of second segment, pale cinnamon or light pinkish-cinnamon pollinose, clothed with 

 3'ellowish hair ; remainder of venter agreeing with dorsum in coloration, markings and 

 hair}'- covering, except that pale hind borders on third and fourth segments, though of 

 same depth as above, do not exhibit median, triangular expansions. Wings strongly 

 tinged with mouse-grey ; veins mummy-brown or cinnamon-brown, anterior branch 

 of third longitudinal vein almost rectangular at base, and with an appendix which 

 varies in size in different individuals, and occasionally is entirely wanting ; stigma 

 tawny-olive, usually fairly well defined and conspicuous. Squamae dusky, borders 

 dark brown, fringed with fine, short pale hair. HaUeres dark brown or blackish-brown. 

 Legs : Coxae and trochanters light greyish-olive pollinose, clothed with \'ellowish hair, 

 hind coxae, at least in front, usually clothed mainly with black hair ; femora black, 

 usually more or less greyish pollinose, at least beneath, front femora clothed with black 

 hair, those of middle and hind legs clothed partly with black, partly with yellowish 

 hair ; tibiae cream-buff, approximately distal third of front tibiae, and tips of middle 

 and hind tibiae black or blackish-brown and clothed with black hair, cream-buff area 

 of tibiae clothed with fine, glistening silvery hair, with which black hairs (sometimes 

 especially numerous on extensor surface of hind tibiae) may be intermixed ; tarsi 

 black, clothed with black hair, third and fourth segments of front tarsi in $ only shghtl}'' 

 expanded. 



Holotype and four paratypes caught on Doi Chom Chang, near Chiengmai, 

 N. Siam, alt. 5,000 ft., 16.iv.l921. With reference to these specimens. Dr. Barnes 

 writes : " Taken while attacking me as I was walking through some jungle. This 

 fly, the bite of which is quite painful, is ver}' common in the jungle on the mountain." 



The species just described, although strongly resembling and closely allied to 

 Tahanus [Aiylotus) leucocnematus, Big., is, in the ? sex, distinguishable therefrom 

 inter alia by the frontal calli being wider apart ; by the expanded portion of the 

 third segment of the antenna being shorter and also deeper at the base ; by the short 

 appressed hair clothing the scutellum, post-alar calli, hind margin of the scutum, 

 and hind borders of the third and fourth abdominal tergites being much paler ; by 

 the median triangular expansions of the abdominal bands in question being smaller ; 

 by the black or blackish-brown tips to the front tibiae being at least twice as deep ; 

 and by the wings being somewhat paler, more elongate, more acuminate, and having 

 a more clearly marked stigma. 



