The Diprionidae are known as the conifer sawflies, though they are not the only family to use conifer trees as hosts (others include Siricidae, Pamphiliidae, Xyelidae, and some Tenthredinidae). Many are destructive pests as larvae, and their biology has been relatively well-studied. Diprionids have stout bodies and distinctive antennal characteristics that make adults easy to recognize (Furniss and Carolin 1977).
Augomonoctenus feeds on the cones of their conifer host. Adults of the most common species, A. libocedrii, are small, about 5–9 mm long, robust, and metallic blue-black with a bright red abdomen. They have a small range on the Pacific coast and are seldom collected (Rohwer 1918, Keen 1958, Smith 1993).
There are three described species worldwide, two of which occur in North America (Taeger et al. 2010).
Diprionidae are easily recognized by the distinctive antennae of both sexes and their small, stout bodies. The subfamily Monocteninae can be separated from Diprioninae (Diprion, Gilpinia, Neodiprion, Zadiprion) by the singular comb-like projection from each antennal segment, and by the veins 1A and 2A fused in the fore wing. It can be separated from Monoctenus by the emarginated clypeus and the flat face (Smith 1974b, Goulet 1992).
Natural history details for this genus are only known for A. libocedrii, which feeds as a larva on the incense cedar cones (Keen 1958). The mature larvae burrow into the soil and remain in diapause until pupation and subsequent emergence, which is recorded to occur every two years (Middlekauff 1967). This species does not cause significant damage to the host (Furniss and Carolin 1977).
World: Two species occur in North America, and one, A. smithi, is known from the Sichuan province of China (Wei et al. 2006).
North America: Both North American species are western. Augomonoctenus pilosus is known from southern California (Middlekauff 1967). Augomonoctenus libocedrii has a broader recorded range and occurs in Oregon and northern California (Rohwer 1918, Smith 1974b).
Map data from: GBIF.org (26 June 2019) GBIF Occurrence Download Augomonoctenus
Details about data used for maps can be found here.