Abstract
The morphological differences in the larva and the adult of Tetropium parvulum Casey and T. cinnamopterum Kirby are reported. Diagnostic characters are the urogomphi of the larva. The shape of the eye, scutellum, and genitalic structures and the number of punctures on the pronotum distinguish the adult. The genitalia are also compared with a third species, T. velutinum. Larvae of T. cinnamopterum have been recorded from a number of conifers, while T. parvulum larvae have only been recorded from spruce.A lectotype is designated for T. cinnamopterum. Examination of type specimens confirmed that T. alaskanum Fall is a synonym of T. parvulum and that T. schwarzianum Casey and T. parallelum are close to T. cinnamopterum. A key is given to distinguish T. parvulum from T. cinnamopterum.