Revision of the Nearctic species of Ditomyia Winnertz and a new species from the Neotropical Region (Diptera: Ditomyiidae) Author Fitzgerald, Scott J. text Zootaxa 2020 2020-10-06 4859 2 239 262 journal article 8213 10.11646/zootaxa.4859.2.4 efffbbf9-8fdd-484c-a9c2-933659495b1a 1175-5326 4412963 19608730-D202-4863-AF29-742F9B791732 Ditomyia potomaca Fisher Figs. 3 , 5 , 19–23 , 48 (Map) Ditomyia potomaca Fisher, 1941: 278 . USA : Virginia . HT male (ANSP). Material examined . CANADA : QUEBEC : Gatineau Park , Black Lake trail W. outflow, 24.V–7. VI .2012, waterfall MT , 45º25’57”N , 75º55’19”W , J.M. Cumming & S.E. Brooks , 3 females (2 SFC , 1 CNCI ) ; USA : CONNECTI- CUT : Fairfield Co. , 17 May 1930 , A.L. Melander 1 female ( allotype ) ( USNM ); MAINE : York Co. , West Lebanon , 29 V–11 VI 1990, D.W. Barry , MT , 1 female ( UNHC ); MARYLAND : Montgomery Co. , Glen Echo , 27 April, C.H . Curran , 1 female ( paratype ) ( USNM ); MASSACHUSETTS : Middlesex Co. , Lincoln , 28–31 May 1982 , E. T . Armstrong , Malaise trap , 1 female ( USNM ); VIRGINIA : Fairfax Co. , Holmes Run , ca. ¼ mile NE jct Gallows Rd & I-495, 38º50’N , 77º12’W , MT , 10 April–7 May 2016 , D. R . Smith , 1 female ( SFC ); Fauquier Co. , Phoebe Hall Knipling Outdoor Lab , Bisquit Mtn. Rd. , 38.8074ºN , 77.7224ºW , 11–27 April 2016 , MT , D. R . Smith & O.S. Flint , 1 female ( SFC ); Prince William Co. , Bull Run Mt. Conservancy , 38º49.484’N , 77º41.362’W , 11–27 April 2016 , MT , D. R . Smith & O.S. Flint , 3 males ( SFC ); Prince William Co. , Bull Run Mt. Conservancy , 38º49.484’N , 77º41.362’W , 28 April–19 May 2016 , MT , D. R . Smith & O.S. Flint , 1 male ( SFC ) . Diagnosis . The following characters will distinguish D. potomaca from other Nearctic Ditomyia : Wings hyaline ( Fig. 3 ), antennal flagellomeres pale yellow (sometimes becoming light greyish-brown distally), nearly concolorous with pale yellow pedicel and scape, black spot marking base of each antennal seta strongly contrasting against yellow background color of flagellomere ( Fig. 5 ), mesonotum black to very dark brown ( Figs. 5 , 19 ), male terminalia as Figs. 20–22 , female terminalia as Fig. 23 . FIGURES 13–16. D. euzona , terminalia. 13. Male, lateral. 14. Male, dorsal. 15. Male, ventral. 16. Female, lateral. Scale bars = ca. 0.25 mm. Abbreviations: ae, aedeagus; c, cerci; c1, cercus one; c2, cercus two; gc, gonocoxite; gs, gonostylus; h, hypandrium; hl, hypandrial lobe; p, paramere; s8, sternite eight; t8, tergite eight; t9, tergite nine. FIGURES 17–18. Male terminalia, ventral, with insets showing detail of hypandrium and aedeagal complex. 17. D. fasciata (see “Remarks” under D. euzona ). 18. D. euzona . Scale bars = ca. 0.25 mm. Abbreviations: ae, aedeagus; c, cerci; ea, ejaculatory apodeme; gc, gonocoxite; gs, gonostylus; h, hypandrium; hl, hypandrial lobe; p, paramere. Remarks . Some specimens examined lack yellow bands on abdomen and have all coxae blackish. Distribution ( Fig. 48 ). Northeastern Nearctic; Canada ( Quebec ), USA ( Maine , Connecticut , Maryland , Massachusetts , and Virginia ). Bionomics . Records indicate the flight period is May through early June. Immature stages and life history are unknown. Marshall (2012: 182) included a photograph of two males competing for a single female on a tree trunk (specimens listed only as Ditomyia , but it appears to be D. potomaca ).