Homoneura (Homoneura) acrostichalis ( Meijere, 1915 )

Shi, Li & Yang, Ding, 2014, Supplements to species groups of the subgenus Homoneura in China (Diptera: Lauxaniidae: Homoneura), with descriptions of twenty new species, Zootaxa 3890 (1), pp. 1-117 : 17-18

Homoneura (Homoneura) acrostichalis ( Meijere, 1915)

( Figs 25–33 )

Lauxania acrostichalis Meijere, 1915: 51 . Type locality: Cocos Islands. Lectotype male in ZMAN. Homoneura acrostichalis: Malloch, 1929: 207 . Sasakawa & Ikeuchi, 1985: 494; Sasakawa, 1997: 142; 2002: 54. Shewell in Delfinado & Hardy, 1977: 200.

Diagnosis. Oc short, about half length of anterior or; anterior or as long as or slightly shorter than posterior or. Arista almost bare, with microscopic ray. Mesonotum with a pair of strong acr situated nearly at horizontal level of second post-sutural dc (occasionally 2–3 pairs of strong acr, then only one pair strongest which is situated nearly at horizontal level of second post-sutural dc).

Redescription. MALE. Body length 3.4–3.9 mm, wing length 3.1–4.0 mm. FEMALE. Body length 3.0– 3.7 mm, wing length 2.8–3.8 mm.

Head ( Figs 27, 28 ) yellow. Frons yellow to pale brown, slightly longer than wide and parallel-sided, with sparse short setulae on anterior 1/2, if yellow, a pair of brown medial stripes visible, if pale brown, a narrow stripelike area surrounded base of two or grayish shining, occasionally a thin yellow stripe extending from anterior margin to ocellar triangle; ocellar triangle yellow, oc short, about half length of anterior or; anterior or as long as or slightly shorter than posterior or. Gena about 1/5 height of eye. Parafacial with a row of setulae on ventral 1/2 of inner margin (middle several longer than top and bottom several). Antenna yellow to brownish yellow (occasionally brown on upper 1/2 or only upper margin of 1st flagellomere), 1st flagellomere about 1.5 times as long as high; arista almost bare (with microscopic ray), black except for brownish base. Proboscis and palpus yellow.

Thorax ( Figs 26, 28 ) yellow to brown. Mesonotum with 0+3 dc (1st post-sutural dc clearly behind transverse suture); acr in irregular 8 rows, with a pair of strong acr situated nearly at horizontal level of second post-sutural dc (occasionally 2–3 pairs of strong acr, then only one pair strongest which is situated nearly at horizontal level of second post-sutural dc); prsc shorter than 1st post-sutural dc. Scutellum yellow. Legs yellow. Fore femur with 3–4 pv, 7–8 pd, and ctenidium with 10–14 short setae (female often 10–12, male often 12–14); fore tibia with 1 long preapical ad and 1 short apv. Mid femur with 5–6 a and 1 app; mid tibia with 1 strong preapical ad and 2 strong apv (occasionally female with 1 apv). Hind femur with 1 weak preapical ad and 1 av on apical 1/3; hind tibia with 1 weak preapical ad (occasionally male with 2 preapical ad) and 1 apv. Wing ( Fig. 25 ) clear; subcostal cell hyaline; costa with 2nd (between R1 and R2+3), 3rd (between R2+3 and R4+5) and 4th (between R4+5 and M1) sections in proportion of 6.7:1.7:1; r-m slightly behind middle of discal cell; ultimate and penultimate sections of M 1 in proportion of 1:1.2; ultimate section of CuA1 about 1/8 of penultimate. Halter yellow.

Abdomen ( Fig. 29 ) yellow to brownish yellow, tergite 5 with 1–3 black round spots (only a medial spot, or a pair of lateral spots or both, occasionally no spot, size of spots variable in individuals from different geographical regions) [part of specimens from Guam, male tergites 3–6 (female 3–7) each with two black irregular lateral spots (size variable), male and female tergites 4–6 each with a black medial spot]. Male tergites 5–6 with densely small spines on ventrolateral margins in ventral view. Male genitalia ( Figs 30–33 ): syntergosternite broad and nearly semicircular and partly fused with tergite 6 at middle in posterior view, about twice as high as tergite 5; surstylus small, acute apically in lateral view; hypandrium nearly bar-like in ventral view; postgonite large and curved with a small acute process and three setulae in ventral view; aedeagus wide with two pairs of lateral processes at middle and a pair of dorsal processes apically in ventral view; aedeagal apodeme shorter than aedeagus.

Material examined. 1 ♂ ( USNM), CHINA, Formosa ( Taiwan): Kankau (Koshun), 1912, H. Sauter (det. J. R. Malloch); 1 ♀ ( USNM), CHINA, Formosa ( Taiwan): Chipun, VII. 1912, H. Sauter (det. J. R. Malloch); 1 ♂ ( USNM), Kiribati: Gilbert Islands, Tarawa, III. 1951, R. Catala (det. Sabrosky); 2 ♂, 2 ♀ ( USNM), Guam Island, D. T. Fulloway (no collecting date); 10 ♂, 4 ♀ ( USNM), Micronesia: Ulithi atoll, Fassarai Island, VII. 10. 1946, H. K. Townes, No. 1052 (det. Shewell, 1963).

Distribution. Oriental: China ( Taiwan), Sri Lanka, Japan (Ryukyu Islands); Australian/Oceanian: Australia, Micronesia Solomon Islands. Cocos (Keeling) Islands; American Samoa, Belau, Bonin Islands, Guam, Kiribati ( Gilbert Islands), Marshall Islands, Niue, Northern Marianas, Volcano Islands, Wake I, Western Samoa.

Figures

FIGURES 25 – 29. Homoneura (Homoneura) acrostichalis (Meijere, 1915). Male. 25, 26. body, lateral view; 27. head, anterior view; 28. thorax, dorsal view; 29. abdomen, posterior view.

FIGURES 30 – 33. Homoneura (Homoneura) acrostichalis (Meijere, 1915). Male. 30. syntergosternite and epandrium, lateral view; 31. epandrial complex, posterior view; 32. aedeagal complex, ventral view; 33. aedeagal complex, lateral view. Scale bar = 0.1 mm.