As an identification skill increases for several years of efforts under a microscope looking at ethanol submerged-samples in petri dish and dried specimens in unit tray (Of course, it occasionally needs extraction of male genitalia and female spermatheca for certain taxa), identifications of many common species are conducted under ethanol without making dried specimens or dissection. The first photo below is an example of bark beetle identification in reality under 70% ethanol in petri dish. It is sometimes quite tough to quickly identify species under this condition, especially when similar looking species are teneral (The colour of body is pale, because it is caught before the molting is completely finished. So, the cuticle is still soft).
How many species of bark beetles can you find in the photo above?
The answer is three! Polygraphus rufipennis, Dryocoetes affaber, and Dryocoetes autographus are originally black, red, and dark red, respectively. But, their colours look same when they are collected in the emergence trap because newly emerged adults are likely to be captured in teneral due to the limited space. This is another obstacle for the rapid identification that I’ve often met in petri dish.
Beetles in Deadwood 