(Figs. 13-16)

Acroneuria (Doroneuria) theodora Needham & Claassen, 1922:254.

Holotype ♀ (Cornell University), Yellowstone National Park, Wyoming

Material examined. Montana: Gallatin Co., Hyalite Creek, above Window Rock, 20 August 2004, B. Stark, I. Sivec, 1♀ (BPS). Wyoming: Johnson Co., Middle Fork Clear Creek, 17 August 2004, B. Stark, I. Sivec, 2♂, 2♀ (BPS). Park Co., Lake Creek, Hwy 296, 18 August 2004, B. Stark, I. Sivec, 3♂, 3♀ (BPS).

Egg. Outline oval with short, narrow collar (Fig. 13). Egg length ca. 530 μm, equatorial width ca. 400 μm, collar length ca. 30 μm, width ca. 60 μm. Chorionic surface coarsely punctate in a band ca. 325 μm wide, extending from near collar (Figs. 14, 16) to smooth opercular band surrounding lid. Lid with obscure, irregularly shaped follicle cell impressions, but punctations absent (Fig.). Micropylar row located on lid; orifices raised, canals obscure (Fig. 15).

Comments. Eggs of Doroneuria are large, oval, and have small collars. The chorionic surface has a broad median zone of shallow pits, a narrow smooth opercular band and micropyles located on the lid near the anterior pole (Figs. 9, 13). The eggs of the two species are quite similar, but differ subtly among specimens examined in two respects. The punctate zone for D. theodora eggs extends nearer the collar and is, therefore, considerably broader in that species than in D. baumanni (Figs. 10, 14). In addition, the lid of D. theodora eggs lacks punctations, whereas in D. baumanni this area has obscure punctations which outline the irregular margins of follicle cell impressions (Fig. 12).