Conchopus acrosticalis (Parent, 1937)

(Figs. 1, 2, 3, 18 a)

Cymatopus acrosticalis Parent, 1937: 69 . Williams, 1939: 314; McKay, 1945: 206; Hardy, 1952: 454; Dyte, 1959: 140; Sunose & Satô, 1994: 655.

Paraphyrosylus acrosticalis (Parent): Hardy & Kohn, 1964: 251.

Conchopus acrosticalis (Parent): Takagi, 1965: 52; Masunaga et al., 2005: 439.

Thambemyia acrosticalis (Parent): Meuffels & Grootaert, 1984: 152; Bickel & Dyte, 1989: 406; Nishida, 1992: 98, 1994: 92, 1997: 78, 2002: 95; Yang et al., 2006: 255.

Diagnosis. Small-sized species (2.9–3.2 mm in body length) characterized by 1st flagellomere twice as long as thickness; halter yellow. In male, M1+2 not thickened, apical section of M3+4 2.4 times as long as discal crossvein; fore tarsomere 1 with small basal lobe 1/3 as long as tarsomere 1, rather weak ventral bristle at midlength, and weak apical swelling; longer dorsal bristle of fore tarsomere 2 at middle; mid tibia flattened, and with long erect bristles and setae on anterior and posterior surfaces; mid tarsomere 1 short setose; ventral lobe of hypopygium very broad on apical 1/2 and slightly longer than cercus.

Material examined (BPBM, LBM, BLKU): Hawai’i: 1ɗ, Hilo, 23.iii.1967, J.R. Vockeroth leg.; 4ɗ, Karapana Pk., 24.iii.1967, J.R. Vockeroth leg.; 4ɗ4Ψ, Wailoku, wet rocks, 30.v.1970, J.H. Tenorio leg.; 15ɗ, Honaunau, 14.xii.2002, K. Masunaga leg. Maui: 2ɗ, Lahaina, 24.ix.1966, T. Saigusa leg.; 28ɗ2Ψ, Kahana, 11.xii.2002, K. Masunaga leg. L ā na‘i: 60ɗ, Kaiolohia Bay, 16.xii.2002, K. Masunaga leg.; 9ɗ, Hulopoe Beach, 16.xii.2002, K. Masunaga leg.; 13ɗ15Ψ, Hulopoe Beach, 17.xii.2002, K. Masunaga leg.; 147ɗ120Ψ, Kaiolohia Bay, 17.xii.2002, K. Masunaga leg. Moloka‘i: 10ɗ5Ψ, Waialua, 4.xii.2002, K. Masunaga leg.

Distribution. Hawaiian Islands (Hawai‘i, Maui, Läna‘i, Moloka‘i).

Remarks. This species is most closely related to Conchopus ciliatus sp. nov. in having simple M1+2 and M 1 in both sexes, and the male of the latter has the following combination of characters different from those of C. acrosticalis: thicker pollinosity of mesonotum; basal lobe of fore tarsomere 1 larger and with many shorter marginal setulae; ventral lobe of hypopygium much shorter than cercus.