Phytomyza astotinensis Griffiths

(Fig. 179)

Material examined. MASSACHUSETTS: Franklin Co., Northfield, 276 Old Wendell Rd., 8.x.2013, em. 15– 26.iii.2014, C.S. Eiseman, ex Solidago canadensis var. hargeri, #CSE1005, CNC384785–384789 (1♂ 4♀) ; Nantucket Co., Nantucket, Squam Swamp, 12.vi.2013, em. 30.vi.2013, C.S. Eiseman, ex Solidago latissimifolia, #CSE630, CNC384813 (1♂) .

Tentatively identified material. MASSACHUSETTS: Nantucket Co., Nantucket, Ice Pond Lot, 26.vii.2014, em. 15–17.viii.2014, C.S. Eiseman, ex Solidago latissimifolia, #CSE1329, CNC384835, CNC384836 (2♀) .

Hosts. Asteraceae: Solidago canadensis L., S. gigantea Aiton (Griffiths 1976), S. * latissimifolia Mill.; adults tentatively assigned to this species were reared from S. flexicaulis L. (Spencer & Steyskal 1986).

Leaf mine. (Fig. 179) Entirely linear, “ 6–12 cm long, remaining narrow (about 1.5 mm wide) terminally, formed entirely on upper surface of leaf, appearing white or greenish-white in reflected light when fresh; faeces deposited as fine particles, mostly forming short beaded strips; larvae leaving leaf through semicircular slit on upper surface before puparium formation” (Griffiths 1976). In some of the leaves we examined, the frass was mostly deposited in an erratic jumble of squiggly fragments, rarely appearing as straight strips for a very short stretch.

Puparium. Black; formed outside the mine.

Distribution. USA: *MA, WI?; Canada: AB (Griffiths 1976).

Comments. Griffiths (1976) found larvae in Alberta in early August and late September, with adults emerging the following spring. He stated that this species seems to be univoltine, and that linear mines found on Solidago earlier in the season were caused by P. solidaginophaga Sehgal. In Massachusetts, P. solidaginophaga larvae were found in May, and those of P. astotinensis, Liriomyza eupatorii, and Ophiomyia maura were all found mining leaves of the same host simultaneously in mid-June. Phytomyza astotinensis is evidently at least bivoltine in Massachusetts, since an adult was reared in late June from a leaf mine collected in the same month, and larvae were found again in October. Females possibly representing P. astotinensis were also reared from larvae collected in late July, with adults emerging in mid-August.