Phytomyza sp. 1

(Fig. 217)

Material examined. MASSACHUSETTS: Berkshire Co., Sheffield, 20.viii.2014, em. 5–9.iv.2014, C.S. Eiseman, ex Sium suave, #CSE1380, CNC384830, CNC384831 (2♀).

Host. Apiaceae: Sium suave Walter.

Leaf mine. (Fig. 217) Upper surface, whitish; entirely linear, but sometimes contorted to form a secondary blotch. Frass is in rather sparse grains.

Puparium. Black; formed outside the mine; humped anteriorly and tapering posteriorly, similar to that of Phytomyza ziziae.

Comments. The only previously known Nearctic Sium miner is an undescribed Canadian species (Lonsdale, unpublished data), which these females do not match. The only other known Sium miner is Phytomyza sii Hering, but this European species has a pale yellow frons and gena, while these females have an entirely dark brown head with a slightly paler whitish tint on the frons between the orbital plates and the gena excluding the ventral margin.