Family common name: common sawflies
Genus: Empria Lepeletier & Serville, 1828
The Tenthredinidae are the most species-rich family and are found throughout the world, in all continents but Antarctica. They are known as the “common sawflies.” They can generally be recognized by a cylindrical body and long, segmented antennae. Otherwise, they come in a variety of colors, sizes, and forms (Goulet 1992).
Sawflies in the Allantinae subfamily are mostly black and shining, sometimes with other colors. They have agricultural importance as some species are pests on cultivated and ornamental plants (Smith 1979a). They can be distinguished from other subfamilies by wing venation (Smith 2003a).
Empria are medium-sized, about 6–8 mm in length. All North American species are mostly black with pairs of light-colored spots on the dorsum of the abdomen (Smith 1979a). They are commonly misidentified because there are few diagnostic characters to distinguish them from other Allantinae (Prous et al. 2011).
Empria can be confused with similar species in the subfamily Allantinae or tribe Empriini. It can be distinguished by paired white spots on the abdomen, angled crossvein, and the lack of a tarsal claw basal lobe (Smith 2003a).
In North America, Empria feeds on Rosa (rose), Fragaria (strawberry), Potentilla (cinquefoil), Rubus (blackberry), Betula (birch), Corylus (hazel), Alnus (alder), and Salix (willow) (Smith 2003a).
The female Empria lays eggs into the leaf tissue along a vein, sometimes in the leaf petiole. Larvae are light gray green, sometimes with longitudinal stripes, slightly flattened like a slug, dull, and finely textured. The young larvae feed singly on the underside of the leaf. At maturity they drop to the ground and build cells with dirt and sand, where they overwinter. Adults emerge in the spring. Described species of Empria are univoltine (Smith 1979a).
Empria obscurata and E. maculata are commonly referred to as the early strawberry slug and late strawberry slug, respectively. They feed on the foliage of cultivated strawberry plants and can be a minor pest (Smith 1979a).
Map data from: GBIF.org (29 October 2019) GBIF Occurrence Download Empria
Details about data used for maps can be found here.