Meiosimyza carolinensis Sasakawa, 2017

Sasakawa, Mitsuhiro, 2017, Insects of Micronesia, Volume 14, no. 10 Diptera: Lauxaniidae (Part 2), Micronesica 2017 (2), pp. 1-5 : 2-3

2. Meiosimyza carolinensis Sasakawa , n. sp.

Type material. Holotype male ( USNM), Kusaie , Hill 1010, Caroline Is., 13 IV 1953, JC, light trap . Paratypes: 1♂, same data as holotype ( USNM) ; 1♀, Mt. Unibot , Tol I., Truk, 30 XII 1952, JG ( BPBM) , light trap; 2♀, Agric. Exp. Sta., Colonia, Ponape, 6 & 11 I 1953, JG ( BPBM) ; 1♀, Mt. Tamatamansakir , Ponape, 18 I 1953, JG ( BPBM) .

Diagnosis. Small, yellowish species, with wing 1.7 (holotype)–2.0 (♂) mm long; head yellow, frontalia with pale brown stripe centrally; thorax largely yellow, mesoscutum pale brown in male but yellow and with six brown vittae in female, with 1 +3 dc, scutellum yellow, brownish anteriorly; costal spinules distinct apically to middle between apices of R 2 +3 and R 4 +5; fore femur without ctenidium of setae, tibiae each with pd; abdomen shining black in male but in female yellow and tergites each with three or four brown spots; phallus nearly thrice as long as phallapodeme ( Fig. 2 ) .

Description. Male. Frons 1.5 times as wide as eye, slightly converging ventrally; parafrontalia with two or (lower one distinctly shorter than upper) os three or four below level of upper or; oc almost as long as lower or, poc twice as long as oc; post-vertical bristles(pvt) cruciate, situated at short distance below vertex; occiput slightly concave dorsally, fit to thorax; eye oblique, slightly higher than wide, with whitish hairs sparsely; face small, flat; gena 1/7 eye height; pm four, shortening anteriorly; antenna with scape and pedicel yellow, first flagellomere pale brown, subquadrate, slightly narrowing and rounded apically, whitish pilose; arista dark brown, as long as eye height, pubescent shortly; palpus black. Mesoscutum densely whitish grey dusted, with four de becoming longer posteriorly, posteriormost de longest; acr in two rows, 1–2 pairs behind transverse suture and posteriormost pair sometimes longer than others; prsc slightly longer than acr; 11 iasetulae in two irregular rows; humerus and notopleuron pale brown; mesopleuron with pale brown median stripe transversely, extending anteriorly to propleuron, 6–8 minute setulae in two irregular rows before mspl and a row of 3–5 setulae at middle between level of mspl and ventral margin of pleuron; sternopleuron brown along dorsal margin, with two stpl. Wing hyaline, faintly yellowtinged anteriorly, with veins brownish yellow; three costal sections in ratio of 4.0: 1.0: 0.8, r-m at proximal position of discal cell, M1 ratio nearly 2.0, ultimate section of CuA 1 about 1/3 length of penultimate; calypter yellow, with fringe whitish; halter yellow. Legs yellow; fore femur with 3–4 long pv setae, hind femur with a long av seta just beyond middle and preapical ad seta shorter than av one; mid tibia with one spur; hind tarsomeres each broadened than others. Genitalia ( Fig. 2 ): epandrium brown; basiphallus narrow, mesophallic sclerites long, distiphallus U–shaped, weakly chitinized, covered by membranous lobe dorsally, with short tongue-like sclerite ventrally. Body length 1.8 (holotype)– 2.1 mm.

Female. Similar to male, but central stripe in frontalia paler and antenna darker than that of male, mesoscutum very sparsely greyish-dusted yellow, with six pale brown vittae, of which median pair between dc- and acr-rows, lateral ones ventrad of prs and pa lines and dorsad of humeri, and sublateral one narrow and shortly on ia-setula rows; humerus and notopleuron yellow; abdomen yellow, T1 with three brown spots (central one sometimes lacking), T2–5 each with four dark brown, quadrate spots before row of marginal setae but those on T5 smaller and paler; wing length 1.7–1.9 mm; body length 2.0– 2.1 mm.

Distribution. Caroline Is.: Truk, Ponape, Kusaie.

Remarks. This is the first record in the Australian-Oceanian Region for the distribution of this Holarctic genus, and this new species is an interesting exhibition of color dimorphism sexually and the phallapodeme is distinctly shorter than phallus [extremely longer in M. rorida (Fallén, 1820) ].

Figures

Figures 1–2. Male genitalia. 1. Kerteszomyia guamensis n. sp. la: epandrium and surstylus, caudal view; lb: phallus and hypandrium, dorsal view (paratype). 2. Meiosimyza carolinensis n. sp., phallus, lateral view (paratype). Scale = 0.l mm.