Sabrosky, C.W.

Proceedings of the Hawaiian Entomological Society

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. 55A New Species of the Dipterous Family Asteiidaefrom HawaiiBy CURTIS W. SABROSKYBureau of Entomology and Plant Quarantine, Agricultural Research Administration,United States Department of AgricultureThe family Asteiidae is one of the smallest and least common ofthe acalyptrate Diptera, and is poorly represented in most collections: It is therefore always of interest to record a new species inthe group.In 1901, Grimshaw (Fauna Hawaiiensis, 3, pt. 1. Diptera, pp.73-74) described two new species of Asteia Meigen from theHawaiian Islands, Asteia hawaiiensis and A. apicalis, and recordeda third merely as "Asteia sp." From his notes on the last, especiallyhis statement that "the arista appears to be quite bare," it is fairlycertain that he had the species which is herein described as new.His specimen was recorded as "beaten from trees, at a height of3,000 ft. in the Waianae Mts., Oahu," and it will be noted that bothof the present specimens were also taken on Oahu, one of themat 4,000 feet on Mount Kaala (Waianae Mts.).Asteia nudiseta, new species.Black-brown and yellow species, distinguished from all other known speciesof the genus by having the combination of three pairs of dorsocentral bristlesand a bare antennal arista.Female.—Head predominantly shining black, the front anteriorly brown,the narrow cheeks whitish yellow except for black margin, and the lower halfof the face with a broad silver-white crossband extending from eye to eye.Proboscis and palpi yellow. Antennae and the slender bare aristae black, thethird segment dusky yellow on the lower fourth. Front broad, equal to one-half the width of the head. Bristles black, the oral vibrissae, inner and outervertical bristles, and the one pair of fronto-orbitals very long and slender,the latter situated slightly in front of a line drawn through the median ocellus;proclinate divergent ocellar bristles distinct though somewhat shorter thanthe above; postverticals minute.Thorax black, with a broad yellow fascia extending on a slight diagonalacross each pleuron from the fore coxa to the base of the wing, the hypo-pleuron and a narrow upper margin of the sternopleuron, brown to yellow.Scutellum black with apical yellow spot between the bases of the widelyseparated apical scutellar bristles. Mesonotum shining black, only a broadmedian stripe between the dorsocentrals, and also the scutellum, sparselypollinose. Chaetotaxy: Notopleurals 1+2, 1 postalar, 3 dorsocentral (oneof them anterior to the suture), and 1 apical scutellar, all long and strongexcept the posterior notopleurals, which are short and spinelike; one pair ofsubapical scutellars, short, hairlike, and very inconspicuous (obviously over-Proc. Hawn. Ent. Soc, Vol. XIII, No. 1, May, 1947.56looked by Grimshaw in his notes on the genus, p. 73). Upper margin of thesternopleuron with three or four hairs, but only the posterior one is developedas a sternopleural bristle.Abdomen yellow below and on the sides, the dorsum dull brown with twobroad brown bands extending yentrad, apparently on the third and fourthsegments. Distal segments shining black.Legs predominantly yellow, marked with black as follows: Distal portionof all femora, including less than one-fourth of the fore, about one-half ofthe mid, and slightly over half of the hind femora; the bases of all tibiaeslightly; and the distal segment and claws of all tarsi. Empodium notablylong and curved.Wings hyaline, veins brown, venation as figured for Asteia in Curran'sManual (1934, p. 328, fig. 3), except that the apical cell is slightly narrowerat the margin of the wing, and the submarginal cell slightly but distinctlybroader than the widest part of the first posterior cell. Knob of the halteresblack, the stalk yellow.Length 2.5 mm.Holotype, female, Mount Kaala, Oahu, July 25, 1946, "el. 4,000ft., bog at summit" (W.' W. Wirth). Paratype, female, Oahu(J. C. Bridwell). Type No. 58218 and paratype in the United'States National Museum.The only described species in the Pacific area which might beconfused with nudiseta is Asteia atriceps Malloch (1932, BerniceP. Bishop Mus. Bui., 98:115), described from Hivaoa in the Marquesas. That species, however, has four pairs of dorsocentralbristles (one before and three behind the mesonotal suture), onlyone posterior notopleural bristle, all yellow bristles, and a largeprescutellar yellow spot on the mesonotum.The two species might well be considered entitled to genericsegregation from typical Asteia, based on the bare arista, as Malloch (op. cit.) has already observed. I believe that they are theonly two known species of Asteia to possess that character. Asteiadecepta Becker (Canary Islands), included with them by Malloch,is on the contrary a species with an intermediate type of arista(like A, apicalis Grimshaw, q. v.), in which the fundamental zigzagstructure is present but only weakly developed and the aristalbranches are short and can be seen only with high magnification.Aside from the type of arista, however, the species are so similarto the usual Asteia that I agree with Malloch in leaving them inthe genus.Asteia apicalis Grimshaw.Three female specimens agree with Grimshaw's description andare here recorded as that species (Kilauea, Hawaiian NationalPark, August 10 and September 1946, in light trap, coll. W. W.Wirth, C. J. Davis). The arista is almost straight, as he noted, andthe aristal branches are microscopic, but even so the arista is distinctly of the zigzag type and not the slender, straight, bare form57of nudiseta. The specimen before me has only two pairs of long,erect, dorsocentral bristles, the mesonotum is more thickly pollinose,and the yellow stripe on each pleuron is wider than in nudiseta,the knob of the halteres is partly yellow, and the abdomen has abrown dorsum and yellow sides and venter, without any brownbands extending ventrad from the dorsum.

A New Species of the Dipterous Family Asteiidae from Hawaii

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A New Species of the Dipterous Family Asteiidae from Hawaii

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