A New Subspecies of Dendroctonus (Coleoptera: Scolytidae) from Mexico

Dendroctonus pseudotsugae barragani is described as new to science from the Sierra Madre Occidental Mountains in Chihuahua, Mexico. It differs from the nominate subspecies in 10 anatomical features involving the head, pronotum, and elytral declivity and in the manner in which groups of eggs are laid. Cross-mated male and female beetles from Chihuahua and Idaho produced 67% fewer progeny than did pairs of beetles from either locality. Further evidence of isolation of the Mexican population is shown by differences in the species of entomophagous and scolytid insects associated with the two subspecies of D. pseudotsugae.