Material examined. WASHINGTON: Clallam Co., 7.x.2012, em. 6.v.2013, C.S. Eiseman, ex Heracleum maximum, #CSE453, CNC392703 (1♂).
Host. Apiaceae: Heracleum maximum W. Bartram.
Leaf mine. According to Griffiths (1973), the mine is “interparenchymal, pale green when fresh (scarcely contrasting with rest of leaf in reflected light), later indicated by areas of red-brown discoloration; channel basically linear, but broad and strongly convolute, in most cases forming irregular secondary blotch; faeces deposited as fine particles irregularly throughout mine, mostly separated by less than 1 mm; larvae leaving leaf through semicircular slit on lower surface before puparium formation.” The only mine we photographed at the time of collection was pale green but plainly visible on the upper leaf surface; it was long, narrow, and entirely linear, very gradually widening and nowhere forming a blotch. Frass was in fine, widely spaced grains.
Puparium. Dark brown or black, strongly arched, with intersegmental boundaries distinctly impressed; formed outside the mine (Griffiths 1973).
Distribution. USA: AK, CA, *WA.