Liriomyza virgo (Zetterstedt)

(Figs. 22, 52)

Material examined. MASSACHUSETTS: Berkshire Co., Lenox, Parsons Marsh, 20.vi.2017, em. 2.vii.2017, C.S. Eiseman, ex Equisetum fluviatile, #CSE3887, CNC939734 (1♀).

Hosts. Equisetaceae: Equisetum fluviatile L., E. palustre L. (Lonsdale 2017).

Larval mine. (Fig. 52) According to Ellis (2018), the egg is laid 1–2 cm from the tip of a lateral branch, and the larva mines basally from here, continuing down the stem. The mines we observed were entirely in the main stem, in some cases proceeding downward but in at least one instance reversing direction early on and mining mostly apically. They were uniformly brown, without obvious frass, and were essentially linear throughout (somewhat blotchy in places).

Puparium. (Fig. 22) Black; formed at the end of the mine, standing at a 90° angle from the stem, with the posterior spiracular processes firmly anchored in the plant.

Distribution. USA: AK, * MA; Canada: AB, BC, MB, NT, ON, QC (Lonsdale 2017).