Family Boreidae - Snow Scorpionflies

Adults dark-colored with an elongated rostrum ("beak"), long antennae, vestigial wings, and long hind legs adapted to jumping; female has a straight ovipositor about the same length as the rostrum, and tapering to a point; males have a blunt rounded abdominal tip

Larvae caterpillar-like but have no abdominal prolegs or conspicuous dorsal setae

Boreus are widespread throughout the Holarctic Region, with 12 spp. in NA, of which only two eastern (B. brumalis and B. nivoriundus)

Hesperoboreus (2 species) are restricted to the west coast from CA to WA

Caurinus includes two species: C. dectes(found in WA and OR), and C. tlagu (found so far only in AK)(2)

In Boreus, the mating behavior differs from other Mecoptera and other insects: the male grasps the female with his slender, hardened wings and moves her to a position above his back, with the lower part of her ovipositor inserted into his ninth (genital) segment(4) (photo of mating Boreus brumalis); the female, on the male's back, has the base of her ovipositor contacting the tip of the male's upturned abdomen.

It was suggested that the Boreidae are more closely related to fleas than to any lineage currently included in Mecoptera(5), but now it seems that each fleas and Mecoptera as now defined are monophyletic groups after all(6)