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PROC. ENTOMOL. SOC. WASH. 95(1), 1993, pp. 17-20 TWO NEW DIXIDAE (DIPTERA) FROM SOUTH KOREA T. Michael Peters Department of Entomology, University of Massachusetts, Amherst, Massachusetts 01003. Abstract.—Two new species, Dixa dolichostyla and Dixa byersL are described with illustrations of their distinguishing morphological characteristics. Di.xa longistyla Taka- hashi is reported from China and another species, Dixa obtusa Takahashi, is reported from South Korea. Key words: Insecta, Diptera, Dixidae, Dixa The Dixidae of eastern Asia are poorly Dixa dolichostyla Peters, known. Only the Japanese fauna has been New Species adequately described (Takahashi 1958), a Figs. 1-2 total of 12 species. Aside from these, only — Dixa giittipennis Thomson has been re- M\x\\. Head: dark brown; antenna ported, as well as two new species known 2.3^ X lengthofthorax, firstflagellomerecy- only from North Korea (Peters 1992). lindrical, slightlyfusiform, width: length 1:8. The paucity ofdixid specimens from the Thorax: Uniformly dark brown in type, Korean peninsula seems odd for two rea- withoutdistinctvittae,butinparatypethree sons. First, a number ofmedical entomol- dark brown vittae with pruinose areas be- ogistsfromtheU.S. werestationedin Korea tween on scutum; anterior pronotum with during the Korean conflict. Second, at that 2 setae subequal to width of sclerite; scu- time, dixids were considered by many en- tellum with transverse row of7 setae, with tomologists to be a subfamily ofCulicidae, two setae in longitudinal linebehind central a family widely studied by entomologists in one. Wing:With slight pigmentation around the military. Therefore, one might expect base ofR 2+3, length ofwing blade 3.45- that fair numbers ofdixids exist in one or 3.6 mm (3); Scjoins C basad to fork ofRs, more major U.S. repositories. m-cubroken; A, faintlydistinguishable; few M The U.S. National Museum has only one widely spaced macrotrichia on basad of dixid specimen from South Korea, identi- r-m; R2+VR3 as 1:1.21-1.25; M3^4:M,+. as fied by me as Dixa obtusa Takahashi. I dis- 1:1.57-1.62; M3,,:Mstas 1:1.29-1.62. //«/- cussed myfrustrations in locatingmore Ko- ter: Hyaline. Legs: Distal spiniform seta on reandixidswithGeorgeW. Byersatthe first tarsomeres 3 and 4 of foreleg, on 1-4 of dipterists' conference in Florida. He said he middle and hind leg; weak basal recurved had been stationed in Korea while he was spiniform seta on tarsomere 5 of fore and in the militaryand would check through his middle leg, absent on hind leg. Tarsomere Korean material for dixids. Not long after- 1 of foreleg with one very long seta near wards, I receiveda loan from the Snow Mu- base, locatedabout itsown length from bas- seum initiatedbyGeorge Byers. Itconsisted al end oftarsomere, 2x length ofother leg oftwopreviouslyundescribeddixidspecies, setae;clawsofforeandmiddleleglong, with the subject ofthis paper. 4 long teeth on venter, hind claws much PROCEEDINGSOFTHE ENTOMOLOGICALSOCIETY OF WASHINGTON 18 Figs. 1-*. Dixadolichostylalateralview(Fig. 1),ventralview(Fig. 2);Dixabyersidorsalview(Fig. 3),lateral view(Fig. 4). VOLUME NUMBER 95, 1 19 smaller, with few weak hairs; femur tibia apical spinose projection; gonostylus with- : : tarsus length offorelegs as 1:1.18:1.5, mid- out setae, curved, sharply pointed apically; dle legs as 1:1.0:1.5, hind legs as 1:1.13:2.0. tergite 10with prominentunsegmentedcer- Terminalia: gonocoxite without basal lobe; ci, spinose on posterior margin; ejaculatory apicallobepointed,withspineson posterior duct sclerotized, very long, severely twisted margin; gonostylus simple, curved, elon- in middle; as in Figs. 3-4. gate;tergite 10withheavilysclerotizednon- Specimens examined.—Holotype, 18 segmented cerci; ejaculatory duct short, milesNEofSeoul, SouthKorea, intheCen- heavily sclerotized; as in Figs. 1-2. tral National Forest. Collected by George Specimens examined.—Holotype, off W. Byers on 14 August 1954 at 400'-500' Hwy. #20, 8 mi SW ofKangnung, So. Ko- elevation. Deposited in the University of rea. 128°47'E, 37°42'N, 1925' elevation. Michigan Zoology Museum, Division of Collected by George W. Byers on 8 June Entomology. 1954. One male paratype from Central Na- Itakepleasurein namingthisspeciesafter tional Forest, 18 mi NEofSeoul, So. Korea. George Byers to honorhisdedication to en- Collected at 400-500' elevation on 29 May tomology, taxonomy and the Nematocer- 1954 by George W. Byers. Deposited in the ous Diptera. University of Michigan Zoology Museum, The 2 species described above increase Division ofEntomology. thenumberofdixid speciescollected on the Dixa byersi Peters, New Species vEiaosutsAlsyikannomwaninolnalnydftroo7m. JTawpoanspheacvieesbpereen- Figs. 3-4 collected on the mainland: Dixa ohtusa — M\i\\. Head: dark brown; flagellum Takahashi in South Korea and Dixa lon- missing. Thorax:distinct dark brown vittae gistyla Takahashi in China. Dixa guttipen- on scutum, pruinose and yellowish-brown nis Thomson is known only from China. between; anterior pronotum dark brown, Two other species, Dixa orientalae Peters with 5 short setae; dark-brown posterior and Dixella corensis Peters, have only been pronotum with a short seta on upper mesal collected in North Korea. area;pre-episternumwith 3 setae; scutellum Some readers may question my place- with transverse row of eleven setae, Vi as ment ofD. byersi in the genus Dixa, since longas width ofhalter pedicel. Wing: with- the antennal flagella are missing. Most keys out pigmentation; length ofwing blade 2.7 to adult Dixidae rely heavily on antennal mm (<5); Sc joins C basad to fork of Rs, characters to determine genus, with some m-cu incomplete, but not broken in middle others split out by venational differences. as in most other species with broken m-cu, Thus, Neodixa Tonnoirand Nothodixa Ed- with portion of m-cu from Cul solid, that wards are separable from the other genera M M from is missing; in basal radial cell by venational differences (unbranched R.+j with macrotrichia on distal %; R. vR, as in the former, r-m basal to fork ofRs in the , 1:1.75; M3,4:M,,, as 1:1.55; M3,4:Mst as latter). This leaves Dixa Meigen, Meringo- 1:1.91. Legs: Only tarsomere 1 ofpro- and dixa Nowell, Paleodixa Contini, Mesodixa mesothoracic legs present, without distal Belkin and Dixella Dyar and Shannon. Of spiniform setae; all other tarsomeres miss- these, Dixella Dyarand Shannon is without ing. Femur: tibia length offorelegas 1:1.14, pre-epistermal setae, and Meringodixa of midleg as 1:1.0, of hind leg as 1:1.06. Nowell, Mesodixa Belkin, and Paleodixa Terminalia: basal lobe ofgonocoxite large, Contini lacka basal lobe on thegonocoxite. rounded,with4prominentapical setae;api- For these reasons, and because ofa lack of cal lobe smaller than basal lobe, slender, associated larvae, D. byersi is placed in the sharply pointed apically, with another sub- genus Dixa Dyar and Shannon. . 20 PROCEEDINGS OFTHE ENTOMOLOGICALSOCIETY OFWASHINGTON The two species described herein may be Literature Cited distinguished from the 4 other "meniscus Disney, R. H. L. 1975. A Key to the Larvae, Pupae midges" (Disney, 1975) ofthe genus Dixa and Adults ofthe British Dixidae (Diptera). The known from the Asian palearctic mainland MeniscusMidges.FreshwaterBiologyAssociation bythefollowing: DixaguttipennisThomson Sci. Publ. No. 31. 78 pp. is the only species with elaborately pat- Peters,T. M. 1992. TwonewDixidae(Diptera)from North Korea. Proceedings ofthe Entomological terned wings, Dixa longistyla Takahashi is Society ofWashington 94; 157-161. the only known species with a group of 3 Rozkosny, R. 1990. Family Dixidae, pp. 66-77. In long setae on tarsomere one ofthe foreleg, Soos, A. and L. Papp,eds.. CatalogofPalaearctic Dixa orientalae Peters is the only species Diptera. Vol. 7. Elsevier, N.Y. with a basal spiniform seta on tarsomere 3 Takahashi, M. 1958. Revision ofJapanese Dixidae. ofthe middle leg, and Dixella obtusa Taka- Mushi 32:1-18 with 6 plates. hashi is the only species with a distinct swelling in the middle offlagellomere 1