USA, Pennsylvania, Spring Brook Twp., Expt. no. C4b, 1 ad. (♀), 1945.v.12, and same locality, no. C4e, 6 ad. (1♂, 5♀), 1 juv. 5, both R.I. Sailor leg.

Holotype, ad. 9 (♀), USA, Alaska, 15 mls N of Fairbanks, 1949.iv.28, S. Lienk leg.

Latinised from the old Aleut word ‘alyeska’, meaning mainland (referring to the collecting site on the Alaskan mainland).

Kionopauropus alyeskaensis n. sp. seems to be in a group of its own because it has long and slender antennal branches and 4-parted anal plate, characters not found in species described up to now.

Length. ?, specimen two-parted. Head (Fig. 1). Setae of medium length, striate, tergal ones somewhat clavate, lateral ones cylindrical. Relative lengths of setae, 1st row: a1=a2=10; 2nd row: a1=16, a2=17, a3=20; 3rd row: a1=12, a2=13, 4th row: a1=12, a2=15, a3=?, a4=37; lateral group setae: l1=25, l2=20, l3=?. Ratio a1/a1-a1 not possible to measure. Temporal organ in tergal view narrow, short, ≈0.8 of shortest interdistance; pistil and pore not ascertained. Head cuticle glabrous.

Antennae (Fig. 2) not complete, on segment 4 only three setae found, all thin, cylindrical, striate, their relative lengths: p=100, p’=67, r=10. p as long as tergal branch t, the latter cylindrical, 5.2 times as long as greatest diameter and 1.2 times as long as sternal branch s. The latter branch 3.6 times as long as greatest diameter, anterodistal corner more truncate than posterodistal one. Seta q thin, cylindrical, striate, 0.7 of the length of s. Flagella lost. Globulus g longish, with stalk included 2.7 times as long as wide, 0.5 of the length of s, diameter of g 0.9 of greatest diameter of t, ≈11 bracts, capsule subspherical. Antennae glabrous.

Trunk. Collum segment hidden. Setae on tergites only partly available for study, those studied thin, cylindrical, proportionately long.

Bothriotricha (Figs 3, 4). T1, T2 and T4 lost; proximal 2/3 of T3 (Fig. 3) with thickened axes with distinct oblique pubescence, distal 1/3 very thin with short pubescence; T5 (Fig. 4) thin with short pubescence.

Legs (Figs 5, 6). Setae on coxa and trochanter (Fig. 5) of leg 9 furcate, main branch clavate, secondary branch subcylindrical, a little shorter than main branch, both branches with short oblique pubescence. Tarsus of leg 9 (Fig. 6) straight, tapering, 4.7 times as long as greatest diameter; proximal seta outstanding, curved, tapering, pointed, with depressed pubescence, 4 times longer than straight, cylindrical, blunt, striate distal seta. Cuticle of tarsus glabrous.

Pygidium (Fig. 7).

Tergum. Posterior margin rounded. a-group setae thin, tapering, pointed, curved inward; st cylindrical, blunt, distinctly pubescent, curved inward and converging; relative lengths of setae: a1=10, a2=9, a3=13, st=4. Distance a1-a1 0.8 of the length of a1, distance a1-a2 3.3 times as long as distance a2-a3, distance st-st 2.3 times as long as st and inconsiderably longer than distance a1-a1.

Sternum. Posterior margin with shallow indentation below anal plate. Relative lengths of setae (pygidial a1=10): b1=15, b2=5. Both setae cylindrical, blunt, striate.

Anal plate 4-branched by three deep posterior V-shaped incisions, median one deepest and broadest, lateral branches cylindrical, submedian branches triangular, cut squarely distally; each branch with cylindrical appendages projecting backward, those of inner branches about 0.5 of the length of those on lateral branches, appendages curved inward; plate and appendages glabrous.

USA, Indiana, Bloomington, 37 ad. (36♀, 1 sex?), 1 ?ad.(sex?), 2 subad. 8(♀), 2 stad. ?(sex?), “Eurypauropus 93 Bollm. Col.?”.

Holotype, ad. 9(♀), USA, Virginia, Fairfox County, Dead Run, 1948.x.10, E.A. Chapin leg. – Paratype, 1 ad. (♀), same data as holotype. – Non type material, 1 subad. 8 (♀), same data as holotype.

From the Latin ‘arcuatus’ = bend like a bow (referring to the curved antennal globulus g).

Eurypauropus arcuatus is close to the two species earlier known from North America, Eurypauropus spinosus Ryder, 1879, and Eurypauropus washingtonensis Scheller, 1985, the former wide-spread in USA, the latter known from National Olympic Park in Washington only. The new species is distinguished from both these species by the shape of the antennal globuli, g, curved in Eurypauropus arcuatus, not straight, globulus g’ of 3rd antennal segment, as long as wide, not at least twice longer than wide, by the shape of the sternal antennal branch s, anterior and posterior margins subsimilar in length, not the posterodistal margin distinctly shorter than the anterodistal one, by the shape of the setae st of the pygidial tergum, simply curved inwards, not S-shaped, and by the shape of the anal plate, no posterolateral appendages, distinct in both Eurypauropus spinosus and Eurypauropus washingtonensis.

Length 1.37–1.42 mm. Antennae (Fig. 8) glabrous. Segment 3 with two setae and globulus g’, segment 4 with three setae. Globulus g’ short, as long as wide. Relative lengths of setae on 4th segment: p=100, p’=84, p”=88. These setae cylindrical, pointed, striate. Tergal seta p 0.5 of the length of tergal branch t. The latter cylindrical, 4.5 times as long as greatest diameter and as long as sternal branch s. The latter branch cylindrical, 4.0 times longer than greatest diameter, anterodistal and posterodistal corners equally truncate; its seta q as setae similar to those of segment 4, and inserted 0.4 from proximal end of s, with length 0.7 of the length of s. Relative lengths of flagella (base segments included) and base segments: F1=100, bs1=(10-)11, F2=66, bs2=10, F3=85(-87), bs3=12. F1 0.9 of the length of t, F2 and F3 1.3 and 1.7 times as long as s respectively. Distal calyces of flagella conical, glabrous. Globulus g slender, 4 times longer than wide, stalk thin, curved, ≈10 thin bracts; diameter of g 0.6 of greatest diameter of t.

Trunk. Setae of collum segment (Fig. 9) short, probably simple, subsimilar, short, tapering, pointed, densely pubescent. Sternite process triangular, pointed anteriorly. Appendages short, wide, caps thin. Process and appendages glabrous.

Tergites with two types of protuberances (Figs 10, 11), large, curved, setose, glabrous, pointed spines, proximally scale-like and evenly spaced on background of more numerous, small crater-like protuberances with pleated sides.

Bothriotricha (Figs 12–14). Relative lengths: T1=100, T2=97(-112), T3=67(-71), T4=117, T5=102(-104). T1 (Fig. 12) and T2 with very thin axes, distal half with short erect pubescence; T3 (Fig. 13) glabrous, with thick axes and distal longish end-swelling, T4 and T5 (Fig. 14) glabrous too but thin, somewhat tapering, blunt distally.

Legs (Figs 15–16). All legs 5-segmented. Setae on coxa and trochanter (Fig. 15) of leg 9 thin, simple, cylindrical, striate. Tarsus of leg 9 distinctly tapering (Fig. 16), (2.8-)3.2 times as long as greatest diameter, two tergal setae and one sternal, all pointed glabrous; proximal tergal seta longest, almost 0.4 of the length of tarsus, (1.8-)2.2 times as long as distal tergal seta and 1.6 times as long as sternal seta. Length of main claw 0.4 of the length of tarsus.

Pygidium (Fig. 17).

Tergum. Posterior margin evenly rounded. Relative lengths of setae: a1=a2=10, a3=(22-)23, st=7. a1, a2 and st similar, tapering, pointed, a1 and st curved inwards with a knee close to proximal end, a2 evenly curved, a1 and st strongly and a2 inconsiderably converging; a3 evenly curved inward and somewhat diverging. Distance a1-a1 (2.1-)2.4 times as long as a1, distance a1-a2 about as long as distance a2-a3; distance st-st 3.2 times as long as st and 1.1 times as long as distance a1-a1.

Sternum. Posterior margin with low posteriomedian bulge below anal plate. Relative lengths of setae (pygidial a1=10): b1=(23-)27, b2=13 and 16 in the holotype, and 18 in the paratype, b3=12. b1 with fusiform, and shortly pubescent base, tapering into a subcylindrical, striate distal half terminated with a small, striate end-swelling; b2 similar to b1 but with cylindrical distal part, proportionately much shorter and without end-swelling; b3 subcylindrical, striate. Length of b1 (as long as -)1.2 times as long as interdistance, b2 0.7-0.9 of distance b1-b2, b3 on the same level as b2, length 1.4 times as long as interdistance.

Anal plate narrowest at base and consisting of two broad lobes posteriorly separated by V-shaped incision ≈0.3 of the length of plate; posterolateral corners without appendages but each with very small tooth; each lobe with a bladder-shaped posteriorly directed appendage with distinct erect pubescence, length of appendages 0.9 of the length of plate.