Phytomyza solidaginophaga Sehgal

(Fig. 206)

Material examined. MASSACHUSETTS: Franklin Co., Northfield, 276 Old Wendell Rd., 18.v.2015, em. 13.iii.2016, C.S. Eiseman, ex Solidago canadensis var. canadensis, #CSE2241, CNC654073 (1♂) ; 18.v.2015, em. 13.iii.2016, ex Solidago rugosa, #CSE2242, CNC654196 (1♀); Hampshire Co., Cummington, along Rte. 9 (east end of town), 18.v.2013, em. 11.iii.2014, C.S. Eiseman, ex Solidago patula, #CSE999, CNC384730 (1♂) ; South Hadley, near Lithia Springs Reservoir, 11.v.2016, em. 9.iv.2017, C.S. Eiseman, ex Solidago caesia, #CSE3428, CNC939718, CNC939719 (1♂ 1♀).

Hosts. Asteraceae: Solidago * caesia L., S. canadensis L., S. * patula Muhl. ex Willd., S. * rugosa Mill., S. simplex Kunth (Griffiths 1976) .

Leaf mine. (Fig. 206) Griffiths (1976) described the mine as “entirely linear, 6–8 cm long, 1.5–2.5 mm wide terminally, formed entirely on upper surface of leaf, appearing greenish-white or greenish-brown in reflected light when fresh; faeces deposited as fine particles, partly forming short beaded strips.” The “beaded strips” in some of the mines we collected were quite similar to the frass in some mines of Liriomyza eupatorii, but based on the material we have seen so far, the presence of discrete frass grains (albeit often in very closely spaced rows) reliably distinguishes Phytomyza mines from those of L. eupatorii .

Puparium. Black; formed outside the mine.

Distribution. * USA: MA; Canada: AB; empty mines in YT were likely caused by this species (Griffiths 1976).

Comments. As noted by Griffiths (1976), this species is strictly univoltine and its larvae appear earlier than those of any other Solidago miner. In Alberta, larvae have been collected in the first half of June; we found larvae in Massachusetts in mid-May, and the adults emerged about two weeks after their puparia were removed from refrigeration the following year.

The eastern males examined here very closely resemble the holotype, although it should be noted there are slight differences that may be due to geographic variation. There are as many spines along the length of the phallus, but these end closer to the apex of the basiphallus; the hypophallus is complete, not broken medially; the basiphallus, hypophallus and base of the distiphallus appear to be slightly stouter.