Carabidae, Zopheridae, and Tenebrionidae - Basic Carabid Identification

Visual, exterior differentiation of sex: Male specimens of Carabidae tend to (but not all species) possess broader protarsi (small segments seen on the forelegs) than the females of said species, additionally, on the underside of the males' wider protarsi one may find 'hairy' pads. These pads are used by the males of some taxa to maintain a grip on the pronotum of females while mating. Although this form of identification based on the external dimorphism of a fair number of carabid genera may be the best option when specimens may not be collected, the trait does not occur in all genera. In such cases, one must find another form of differentiation.

Female specimens of Carabidae, when not on the move, may flex their posterior, causing the tip of the ovipositor to protrude from the tip of the abdomen, thus making it visible to the viewer.

Cases similar to this may occur if carabid specimens that have already been collected, if euthanized by way of freezing. Where the limbs and jointed portions of the beetle will seize up, or contract, in turn causing the ovipositor or genitalia of the beetle in question to protrude from the abdomen.

Specialised, wide protarsi of male Chlaenius sericeus

Narrow protarsi of female Chlaenius sericeus

If attempting to ID the sex of a carabid while in the field, if you do not have a camera with which you may use to acquire a better view of the specimen, or if the specimen in question happens to be of a size that visual recognition based off of physical characteristics is out of the question, the use of a handheld pocket lens would be recommended.

Antennae: Most carabid beetles have filiform antennae, which are typically fairly long, thin antennae, which are made up of eleven antennomeres, or segments. For the most part, the carabid species which do not have filiform antennae like this are not known in any of the states or provinces covered in this site.