The western pine beetle, Dendroctonus brevicomis LeConte, was sexed. using 5 different criteria: (1) stridulation movement, (2) stridulation sound, (3) configuration of the 7th tergite, (4) configuration of the frons, and (5) configuration of the pronotum. Only criteria 3, 4, and 5 were found acceptably accurate. Criterion 5 was faster to use than 3 and 4. Generally 5 is the best criterion to use in sexing, but other criteria still have limited uses.