(Figs. 14-19)
Perla sabulosa Banks, 1900:242. Holotype ♀ (MCZ), Washington, Yakima
Adelungia arctica Klap {lek, 1916:78. Syntype ♂, ♀ (BMNH?), Arctic America. Synonymy by Ricker (1952) Perla languida Needham & Claassen, 1925:100. Holotype ♂ (Cornell University), Wyoming, Yellowstone River. Synonymy by Ricker (1952)
Material examined. Alberta: Bow River, ca. 1 mi S Cochrane, 3 September 1974, L. Dosdall, 1♂, 1♀ (BPS). California: Siskiyou Co., Klamath River, Sarah Totten Campground, 8 July 1979, B. Stark, K.W. Stewart, 1♂ (BPS). Colorado: Mesa Co., Colorado River, 2 mi SE DeBeque, 11 August 1973, B. Stark, R.W. Baumann, 2♂, 1♀ (BPS). Montana: Lincoln Co., Yaak River, Hwy 2, Yaak River Campground, 19 July 1979, B. Stark, K.W. Stewart, R.W. Baumann, 1♂, 1♀ (BPS). Park Co., Yellowstone River, Pray, 21-26 July 1989, B. Stark, J. Parham, T. Moore, D. Tanner, 20♂, 4♀ (BPS). Park Co., Yellowstone River, Hwy 89, Yankee Jim River Access, 19 August 2004, B. Stark, I. Sivec 2♂, 1♀ (BPS). Utah: Summit Co., Weber River, 1 mi W Peoa, 16 July 1974, B. Stark, 4♂ (BPS). Uintah Co., Green River, Dinosaur National Monument, 2 July 1974, B. Stark, 5♂ (BPS). Washington: Yakima, 1♀ (sabulosa holotype, MCZ).
Adults of this species are illustrated in Baumann et al. (1977), Stark (2004), Stark & Gaufin (1976) and Stewart & Stark (2008), larvae are described and illustrated by Stewart & Stark (2002), and SEM images of the eggs are available in Stark (2004) and Stark & Gaufin (1976). Additional images and comparative details are provided below for the egg. Egg. Spindle shaped with low button-like collar (Figs. 14-15). Total length ca. 440-450 μm, equatorial width ca. 314-320 μm. Anchor cap- shaped, margins studded with mushroom bodies, but crown bare (Fig. 18). Most of chorionic surface covered with obscure, hexagonal follicle cell impressions; anterior pole covered with more prominent follicle cell impressions for apical length of ca. 73-79 μm (Fig. 16); external membrane on anterior pole bearing a single mushroom body over each follicle cell impression (Fig. 17). Micropylar row subequatorial, located ca. 170-180 μm from anterior end (Fig. 19).
Comments. The holotype female of this species was studied by one of us (BPS) in 1974. Eggs obtained from that female were found to be consistent with those of other populations of C. sabulosa from throughout western North America. Ricker (1938) saw and illustrated the types of C. arctica and stated they were in the British Museum. Kimmins (1970) list does not include this species, consequently, we are uncertain where these types are presently located.