Boreus borealis Banks, 1923
Diagnosis: Body dark brown on head and glossy black on abdomen. Male length, pinned, 5.0 mm; female length, pinned, 5.4 mm. Ratio of length of maxilla-labial complex to rostrum = 0.84. No bristles on pro-, meso, and metanota. Male forewings yellowish-brown and abruptly narrowed at mid-length, with 36 mesal and 13 lateral spines. Female forewings yellowish-brown, oval, covering hindwing. Male 8th tergum and sternum fused; 9th tergum and sternum not fused. Hood very broad (about 4/5 width of tergum) with medial ridge and numerous long setae near ridge below crest of hood.
Distribution – Geographical: This species is only known from less than a dozen specimens collected on St. Paul Island in the Pribilof Island group in the Bering Sea off of Alaska.
Distribution – Temporal: May, July, August. This species probably emerges as adults later in the season than other boreids due to the harsh climate and high latitude.
Ecology: St. Paul Island has been described as having a maximum elevation of 203 feet and dominant vegetation of cottonsedge tundra (Penny, 1977). It has frequent fog, gales, and violent seas.
Biology: Nothing is known of immature stages or life cycle.
Notes: This species belongs to the californicus species group in which males have a large hood on the 9th abdominal tergum that has a medial ridge dividing the hood into two halves. Other members of the group are B. californicus, B. coloradensis, and B. intermedius. Boreus borealis can be separated from other members of this species group by the width of the male hood and numerous interior setae on the hood.
The name borealis is derived from the Greek boreus, which means northern.
Banks, N. 1923. Mecoptera. North American Fauna, 1923 (46):158.
Penny, N.D. 1977. A systematic study of the Family Boreidae (Mecoptera). University of Kansas Science Bulletin, 51(5)141-217.