Liriomyza cf. cracentis Lonsdale

(Fig. 74)

Material examined. ILLINOIS: Cook Co., Glencoe, Chicago Botanic Gardens, McDonald Woods, 42°8′56.66″N 87°47′21.99″W, 12.vi.2018, em. by 27.vi.2018, J.F. Steffen, ex Eupatorium rugosum, CNC 1135572 (1♁).

Hosts. The label of the Liriomyza cracentis holotype indicates a host of “ Euperomum maculata ”, possibly referring to Eupatorium maculatum, a synonym of Eutrochium maculatum (L.) E.E.Lamont (Asteraceae) (Lonsdale 2017a). The Illinois specimens were reared from Ageratina altissima (L.) R.M.King & H.Rob., which like Eutrochium is in the tribe Eupatorieae.

Leaf mine. (Fig. 74) Upper-surface, greenish to whitish, entirely narrow and linear; the photographs provided by J. Steffen do not show the entire mines, but no frass is evident in the portions photographed.

Puparium. Details not recorded, but presumably formed outside the mine.

Phenology and voltinism. All known specimens tentatively identified as Liriomyza cracentis have been reared or captured between late June and mid-July. Larvae are present in June.

Distribution. The Liriomyza cracentis holotype was collected in Canada: QC, and a tentatively identified male was collected in ON. The new material is from USA: IL; also see Comments below.

Comments. Based on the host, leaf mine, and adult characters, this fly is possibly conspecific with the Massachusetts female discussed by Eiseman & Lonsdale (2018) as Liriomyza sp. 2; the mines in both cases seem consistent with Spencer & Steyskal’s (1986) unidentified leaf mine #4 (known from DC, MN, and WI). We should note, however, that the photographed mines are not the exact ones from which the Illinois specimen was reared; no host material was preserved, and after the adult emerged, J. Steffen returned to the group of plants from which the mines had been collected and photographed old, vacated mines that at least superficially resembled them.