Calycomyza promissa (Frick)

(Figs. 20, 117)

Material examined. COLORADO: Larimer Co., Estes Park, 1.ix.2015, em. by 10.ix.2015, N. D. Charney, ex Symphyotrichum ascendens, #CSE2041, CNC654334 (1♂) ; Park Co., High Creek Fen, off of Rte. 185, 13.vii.2015, em . 25.vii.2015, C.S. Eiseman, ex Symphyotrichum, #CSE1828, CNC564673 (1♂); MASSACHUSETTS: Berkshire Co., Stockbridge, Agawam Lake, 14.viii.2017, em . 20.viii.2017, C.S. Eiseman, ex Symphyotrichum puniceum, #CSE4152, CNC939711 (1♀); Franklin Co., Northfield, 276 Old Wendell Rd., 4.viii.2017, em . 10.viii.2017, C.S. Eiseman, ex Symphyotrichum lateriflorum, #CSE4101, CNC939663 (1♂); NORTH CAROLINA: Durham Co., Durham, 20.v.2015, em. by 25.v.2015, T.S. Feldman, ex Symphyotrichum, #CSE1581, CNC564611, CNC564612 (1♂ 1♀) ; Scotland Co., Laurinburg, St. Andrews University, 15.v.2015, em . v.2015, T.S. Feldman, ex Symphyotrichum, #CSE1563, CNC564633 (1♂); 17.viii.2015, em. 18.viii.2015, T.S. Feldman, ex Symphyotrichum pilosum, #CSE2122, CNC564666 (1♀); 15.ix.2015, em. 24–28.ix.2015, T.S. Feldman, ex Symphyotrichum pilosum, #CSE2098, CNC653942, CNC653943 (2♂); x.2015, em. by xi.2015, T.S. Feldman, ex Symphyotrichum, #CSE2160, CNC653937 (1♀); 11.v.2016, em. 18.v.2016, T.S. Feldman, ex Symphyotrichum pilosum, #CSE2469, CNC653957 (1♀); OKLAHOMA: Payne Co., Mehan, 36.014339° N, 96.996744° W, 23.iii.2016, em . 2.iv.2016, M.W. Palmer, ex Symphyotrichum praealtum, #CSE2651, CNC634798, CNC634799 (1♂ 1♀); 23.iii.2016, em. by iv.2016, M.W. Palmer, ex Symphyotrichum drummondii, #CSE2657, CNC653987 (1♂); 24.iii.2016, em. 30.iii.2016, M.W. Palmer, ex Symphyotrichum oolentangiense, #CSE2659, CNC653995 (1♀); 6.vi.2016, em. by 17.vi.2016, M.W. Palmer, ex Symphyotrichum ericoides, #CSE2596, CNC634974, CNC634975 (2♂); 6.iii.2017, em. 17.iii.2017, M.W. Palmer, ex Symphyotrichum drummondii, #CSE3744, CNC939908 (1♀); 19.iii.2017, em. 29–31.iii.2017, M.W. Palmer, ex Symphyotrichum drummondii, #CSE3746, CNC939909, CNC9399 10 (2♂); 24.iii.2017, em. 3.iv.2017, M.W. Palmer, ex Symphyotrichum ericoides, #CSE3731, CNC939890 (1♀).

Tentatively identified material. FLORIDA: Lake Co., Alexander Springs, 26.iii.2013, em. 12–18.iv.2013, C.S. Eiseman, ex Ampelaster carolinianus, #CSE270, CNC384821–384824 (4♀) .

Hosts. Asteraceae: Symphyotrichum *ascendens (Lindl.) G.L. Nesom, S. chilense (Nees) G.L. Nesom (Frick 1956), S. * drummondii (Lindl.) G.L. Nesom, S. *ericoides (L.) G.L. Nesom, S. lateriflorum (L.) Á. Löve & D. Löve, S. *oolentangiense (Riddell) G.L. Nesom, S. * pilosum (Willd.) G.L. Nesom, S. * praealtum (Poir.) G.L. Nesom, S. * puniceum (L.) Á. Löve & D. Löve. Records of unspecified “ Aster ” spp. from Ontario (Spencer 1969) likely also represent Symphyotrichum spp.; we have found no mines resembling those of Calycomyza promissa on other asters, with the exception of Ampelaster carolinianus (Walter) G.L. Nesom, which is restricted to the southeastern USA. The mines and puparia on Ampelaster are entirely consistent with C. promissa, as are the females reared from this host, but males are needed to confirm their identity.

Leaf mine. (Fig. 117) Initially linear; upon reaching the midrib it becomes a large, white blotch centered on the midrib that soon obliterates the linear portion. Frass is centrally deposited on the floor of the mine below the midrib in pellets and streaks coalescing to form a black mass. An emergence slit is cut at the edge of the mine (Frick 1956). The mine is generally circular but is irregular at the edges (Spencer 1969). Some of the mines we examined matched this description, but others were largely or entirely to one side of the midrib, with the frass deposited in a large central mass. In some mines the two epidermises were well separated, producing a blisterlike buckling of the leaf, and there were frequently irregular patches of green, uneaten parenchyma attached to the upper epidermis. The largest (and sometimes only) green area was always in the center of the mine, partially concealing the frass deposit. The initial linear portion was likewise green and interparenchymal, sometimes beginning as a white line on the lower surface.

Puparium. (Fig. 20) Brown; formed within the mine, “upon a slender pile of frass of about one-half the puparial length” (Frick 1956). In examples we examined, the frass pile ranged from less than one fifth to one half the puparial length, but always formed a narrow pedestal that held the puparium above the floor of the mine. Larvae are normally solitary, but one mine contained two puparia.

Distribution. USA: CA, *CO, FL (leaf mines and females only), LA, *MA, NY, *NC, *OK; Canada: MB, ON.