Pachybrachis bivittatus (Say, 1824)

Barney, Robert J., 2019, Key to All Sixty-Four Species of Pachybrachis Chevrolat (Coleoptera: Chrysomelidae: Cryptocephalinae) in the Eastern USA, The Coleopterists Bulletin 73 (1), pp. 85-96 : 91

4. Pachybrachis bivittatus (Say, 1824)

Barney et al. 2013: habitus 2, map 2.

Remarks. Say’ s type, reported as found “near the Rocky Mountains”, is not extant ( Weiss and Ziegler 1931). Fall (1915) made no mention of seeing a type and noted that Bowditch often mistakenly used the name P. viduatus for P. bivittatus .

Pachybrachis bivittatus is one of the largest, commonest, most widespread, and easily identifiable species in the eastern USA. It is likely found in all 48 contiguous states. Riley et al. (2003) listed 34 states, five Canadian provinces, and Mexico. Further research may reveal that multiple species are represented.

There are multiple reports of P. bivittatus being found on Salix spp. (Salicaceae) , which I can confirm from personal experience in Arizona, Colorado, Florida, Illinois, Indiana, Kansas, Nebraska, Utah, and Wisconsin. Pachybrachis bivittatus is one of the few species of Pachybrachis whose biology has been studied in any detail. Egg and larval case formation was reported by Lawson (1976). LeSage (1985) described the eggs and larvae of P. bivittatus and confirmed that larvae feed in the leaf litter of dead willow.