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, T 1 with three brown spots (central one sometimes lacking), T 2–5 each with four dark brown, quadrate spots before row of marginal setae but those on T 5 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.