Silba Macquart

GENUS: SILBA MACQUART, 1851: 277 Silba arcana McAlpine 1960: 369 DISTRIBUTION: Recorded by McAlpine (1960), who figured the male and female genitalia, from Zimbabwe. New to Namibia and Zambia. MATERIAL EXAMINED: NAMIBIA: 4 males, 4 females, Katima Mulilo District, Salambala campsite, 17°50’01”S, 24°36’09”E, 26–28.ii.2001, A.H. Kirk­Spriggs & E. Marais, Malaise trap; 1 male, Tsumeb District, Mannheim Research Station, 19°10’10”S, 17°45’33”E, 31.i–07.ii.2000, A.H. Kirk­Spriggs, Malaise trap, mango plantation; 1 male, Tsumkwe District, Kano Vlei, 3 km N of, 19°17’15”S, 20°21’03”E, 19.xii.1998, [A.H.] Kirk­Spriggs, [E.] Marais & [D.J.] Mann, at light, dry woodland; 1 male, Tsumkwe District, Xawasha pan, 2 km W, 19°09’57”S, 20°52’55”E, 26–27.xii.1998, [A.H.] Kirk­ Spriggs, [E.] Marais & [D.J.] Mann, Malaise traps; 1 male, ZAMBIA: 1 male, Choma, 5km S, 16 49'S, 26 55'E, 15.iii.1993, E. Marais. All specimens in National Museums of Namibia, Windhoek. Silba budongo sp. nov. Description. Male: Head: Eyes bare. Frons almost parallel sided, approximately half the width of an eye, subshining and flat with short hairs which are one quarter as long as the orbital bristle over most of the frons, longer hairs present on anterior margin just above lunule. Orbital plates shining and bare. Lunule with five hairs. When seen from above lunule, face and parafacials slightly silvered. Anterior genal setae extending anteriorly along the mouth margin in a single row of five hairs, the two basal ones being the strongest hairs on the genae, twice as long as the other hairs. Antenna entirelly black: first flagellomere three times longer than it is deep, reaching down over the mouth edge. Aristal plumosity at its maximum extent equal to the depth of the first flagellomere. Thorax: Thoracic disc shining in contrast to the rather heavily dusted scutellar disc. One propleural and one hair­like stigmatical bristle. Anepisternum with three strong anterior bristles and four strong posterior bristles. Katepisternum with two strong bristles. Scutellum heavily dusted on the disc, bare dorsally, on the margins between the strong lateral and apical bristles, with two hairs on one side and three on the other, a crossed pair present between apical bristles, all these hairs short, only about one fifth the length of the apical bristles. Squamae and fringes pale yellow, wings slightly fumose, outer crossvein slightly bent. Wing length 4.5mm. Legs all black. Male genitalia: Fig. 2; 3,4,5. In lateral view epandrium higher than it is broad, rather flat on ventral and anterior surfaces, with a semi­circular excavation anterodorsally, bearing moderately long hairs posteriorly and ventrally. Cerci tall, narrow and rounded, at least half the height of the epandrium, bearing moderately long hairs over most of their surface. Surstylus extending beyond the shell of the epandrium as a spike­like process anteriorly and as a small rounded projection posterioventraly. In ventral view surstyli with a row of fine hairs along their ventral margins, these hairs becoming longer and stronger posteriorly. Basal lobe with six small black teeth, a pair of downward pointing spicules situated just below the base of the cerci. Aedeagus a simple J­shaped tube with a narrow band of spicules present between the basal and apical portions Female: Unknown. Differential diagnosis. With entirelly black legs, pale squamal fringe and a rather simple aedeagus with spicules this species shows similarities to Silba fraterna McAlpine, 1956 known from Kenya and South Africa. It can be distinguished from this species by the bare eyes while they are “sparsely but uniformly pubescent” in S. fraterna, and; the plumosity of the arista is equal to the depth of the first flagellomere, it is only half this width in S. fraterna. TYPE MATERIAL: Holotype male. UGANDA: Budongo Forest, 14 xi. 1972, H. Gønget leg. Only known from the holotype. Specimen in the Zoological Museum Copenhagen. Etymology. The specific epithet refers to the locality (Budongo Forest) where this species was collected. Silba calceus sp. nov. = Silba virescens Macquart? of McAlpine, 1960. Description. Male: Head: Eyes bare. Frons narrowing only slightly from level of the ocellar triangle to level of antennal sockets where it is approximately half as wide as an eye, flat and subshining with short hairs which are one quarter as long as the orbital bristle over most of the frons, longer hairs present on anterior margin just above lunule, subshining and flat. Orbital plates shining and bare. Lunule rather brownish orange with about eight hairs. When seen from above face and parafacials slightly silvered. All hairs on the genae rather short, none longer than the depth of the first flagellomere. Anterior genal hairs extending anteriorly along the mouth margin in a single row of six hairs, the two or three posterior ones being the strongest hairs on the genae but not noticeably longer than the others. Palps broad, at their base wider than the depth of the first flagellomere. First flagellomere three times longer than it is deep, reaching down over the mouth edge; black apart from an orange area on inner surface at base. Aristal plumosity at its maximum extent just over half the depth of the first flagellomere. Thorax: Thoracic disc shining but dusted on the outer margins, bearing hairs less than half the length of the orbital bristle. One propleural and one hair­like stigmatical bristle present. Anepisternum with two strong and below these two moderately strong anterior bristles and three strong posterior bristles. Katepisternum with two strong bristles, the anterior one slightly weaker than the posterior, no hairs behind or below these bristles. Scutellum heavily dusted on the disc, bare dorsally, on the margins between the strong lateral and apical bristles with one hair on one side and three on the other, three hairs present between apical bristles, all these hairs short, only about one sixth the length of the apical bristles. Squamae and fringes whitish, wings with membrane clear. Wing length 3.75mm. Legs all black. Male genitalia: Fig. 3; 1,2,3. Epandrium taller than it is wide, rather flat on the ventral surface and with a semi­circular excavation anterodorsally, bearing hairs at the posteroventral angle and along the ventral margin but none of these particularly long or strong. Cerci forming a rather rounded club, about half the height of the epandrium, the club bearing short hairs. Surstylus extending beyond the shell of the epandrium posteroventrally as a small rounded process, anteriorly as a characteristic shoe­shaped process. In ventral view the surstylus is produced into rounded lobes posteriorly, this bearing a row of fine hairs on its margins, basal lobe bearing four short black teeth. Aedeagus two­segmented forming a simple J­shape, basal and apical portions slender, apical portion with spicules at the tip. Female: Unknown. McAlpine (1960) described and illustrated this species from a single male in his review of South African Lonchaeidae under the name of Silba virescens, but added a question mark after the name showing that he was unsure that this was indeed the true S. virescens. In light of subsequent work on the taxonomy of Silba it is now apparent that the species described by McAlpine is not S. virescens Macquart and as far as I can ascertain the status of this species described by McAlpine has never been clarified. It is however, based on the characters of the male genitalia with its “shoe­like” anterior projection of the surstyli beyond the margin of the epandrium, apparent from McAlpine’s illustration, an easily recognisable species and its occurrence in the Namibian collections has prompted to me clarify its status. I therefore assign it a new name. TYPE MATERIAL: Holotype male Namibia: Opuwo District. Ruacana area, 17 26’ S 14 9’ E, 14.iii.1997, A.H. Kirk­Spriggs. Malaise trap in mango plantation. Specimen in the National Museums of Namibia, Windhoek. The specimen described by McAlpine (1960) from Natal, South Africa, was reared from a decaying avocado and is in the South African National Collection. Etymology. The specific epithet is derived from the Latin calceus, referring to the shoe­like anterior projection of the surstylus. Silba figurata sp.nov. The holotype is slightly damaged with some of the main bristles being absent. Description. Male: Head: Eyes bare. Frons almost parallel sided, pollinose and bearing short hairs no more than one quarter the length of the orbital bristle, with some slightly longer ones present on the anterior margin just above the lunule. Orbital plates shining and bare. Lunule slightly silvered with four hairs on each side, face shining black. Antennae entirelly black: first flagellomere three times longer than it is deep reaching down over the mouth edge. Arista with plumosity at its maximum about as wide as the depth of the first flagellomere. Anterior hairs on the genae extending along the mouth edge as a single row of four hairs, the posterior two of these being the strongest hairs on the genae but not markedly stronger than the others. Palps almost as deep as the first flagellomere. Thorax: shining on the disc with short hairing. One propleural and one stigmatical bristle. Anepisternum with several bristles missing but apparently with two? strong anterior and two? strong posterior bristles. Katepisternum with two strong bristles. Scutellum shining, bare dorsally, margin with three hairs between strong lateral and apical bristles and two hairs between apical bristles, these hairs rather long being almost a third as long as the bristles. Squamae and fringes yellow, wing membrane slightly fumose. Wing length 4.0mm. Legs entirelly black Male genitalia; Fig. 3; 4,5,6. Epandrium taller than it is wide, anteriorly excavated, bearing hairs along the posterior and ventral margins but none of these exceptionally long or strong. Cerci rather large and triangular in shape, sclerotised apical

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