Achoanus hulleyi, n. sp

Munro, H. K., 1924, A New Genus And Species Of Syrphidae (Diptera) From South Africa, Annals of the Transvaal Museum 10, pp. 87-89 : 1-88

Achoanus hulleyi, n. sp .

♂. Length 13.8 mm.; head, length, 2'8 mm., width, 4' 3 mm.; wing, length, II mm.; abdomen, maximum width, 4' 5 mm. (Two specimens.)

Head: hemispherical, wider than thorax, face not conically produced, anterior margin of buccal cavity retreating; oral opening long and narrow. Face: saffron yellow, sides paler and clothed with pale yellow hair, golden tomentum above, and white below; facial tubercle cariniform. Genae: black with white tomentum. Frons: tuberculate, small, shining black, clothed on sides and above with long, black hair and rather sparse, golden tomentum. Lunule: yellow. Antennae: approximated at base; first two joints of equal length, rufous and clothed with short black bristles; third joint oval, rufous with a blackish infuscation except on a narrow margin where it meets the second joint; darker above. (The infuscation is less pronounced in the specimen from the Transvaal.) Arista: black, with minute hairs on the proximal thickened two-thirds. Proboscis: short. Vertical triangle: very long and narrow, three times as long as its base; clothed with black hair except on the apex in front of the anterior ocellus. Ocelli: far forward; posterior ocelli at middle of triangle, anterior ocellus half as far again from them as they are from each other. Eyes: bare, inflated anteriorly above; contiguous for a distance one and a half times the length of the vertical triangle and for twice the length of the frontal triangle. Upper facettes greatly enlarged. Occiput: deeply excavated above, so that the posterior dorsal margin of the eyes and vertex forms a sharp edge on which is a row of short yellowish hairs. Laterally, in the posterior median sinuosity of the eye the occiput widens out and is clothed with a very thick silvery tomentum and long silvery squamous hairs; the latter extend down to t.he lowest corner of the eye where they merge into the long white hairs on the lower part of the occiput. Thorax: dorsum dull black, shining, clothed with yellow hair which does not form a well-defined collar anteriorly; sides of dorsum and pleura yellowish; clothed with long yellow hair and yellow tomentum as in Asarcina . Sterna: blackish in front and on sides, yellowish behind. Legs: slender, yellow, first two pairs clothed with yellow, last pair with black hair; tarsi: black above. Wings: as long as abdomen and thorax together, hyaline with a slight greyish infuscation, and a few yellowish marks towards the base; stigma yellow; veins brown; third longitudinal vein with only a gentle curve downwards. Squamae : rather small; yellow; margin thickened, inner lobe fringed with short yellow hair, outer with long, yellow, branched hairs. Halteres: pale lemon yellow. Scutellum : yellowish translucent; clothed with black hair above, except at base where it is yellowish; hair yellow beneath. Postscutellum: shining black. Abdomen: ovate, wider than thorax; dorsum saffron yellow, clothed with short black hair except longer yellow hair on basal angles. First segment entirely yellow; on the posterior margins of the second to fourth segments is a rather narrow blackish or very dark brown transverse band; the bands become somewhat broader backwards; on the fifth segment the band is reduced and does not reach the outer margins of the s;gment. The anterior edge of each band is not very clearly defined (in the Transvaal specimen the bands are much narrower; the abdomen is badly discoloured, but as far as may be observed, the band on the second segment seems to be almost absent). Hypopygium: small, spherical, concealed and asymmetrical.

C(. Length 14 mm.; head, len~h, 2' 7 mm., width, 4 mm.; wing, length, 10' 5 mm.; abdomen, maximum Width, 4' 9 mm, (Three specimens.) Length II mm.; head, length, 2' 1 mm., width, 3' 4 mm.; wing, length, 10 mm.; abdomen, maximum width, 4' 2 mm. (Two specimens.)

The infuscation on the third antennal joint is not as deep as in the male, but in two specimens it is even more so. Eyes: not inflated above. Frons: narrowed gradually; clothed with hair laterally and above, and golden tomentum laterally, leaving a broad shining black, median stripe from the tubercle to the upper shining black portion of the frons. Vertex: black, with azure blue reflections (this is more pronounced in some specimens than others); clothed with black hair. Ocelli: equidistant. Occiput: with a narrow margin visible above, clothed with fine yellowish tomentum. The transverse abdominal bands are blacker, rather wider, and better defined than in the male. Ovipositor: short, yellow. In other respects the female is similar to the male.

Two of the specimens were captured on the farm Stentor, near Kaapmuiden, in the Transvaal, by Mr L. S. Hulley, who, as a· collector, has done much to increase our knowledge of S. MricanDiptera, and it is with no small pleasure that I give his name to this species.

Cotypes. I ♂, I ♀, Stentor , Barberton district , Transvaal, November, 1919 (L. S. Hulley). 1 ♂, Pretoria, January, 1913 and I ♂, 3 ♀ ♀, East London, May, 1923 (author). I ♂ ( Barberton ) and I ♀ (East London), cotype deposited in the collection of the Transvaal Museum, Pretoria, the remainder being in the author's collection .

Biology. As far as has been observed by the author, this species frequents the same haunts as do most of the species of Asarcina . Like these, it seems averse t~ bright sunlight, and is found among the undergrowth below trees, hovering in the air, and occasionally resting on leaves or twigs.