Geometrinae - Identifying Marks

A number of key features are frequently cited as the most useful characteristics for distinguishing among Geometrine species. Among the most important identifying features on adult moths is the pattern of markings on the dorsal surface of the abdomen. The abdominal segments may bear a series of white spots, spots encircled by a colored margin, a white stripe, or in some instances, no distinct marking on a plain ground color in some shade of green. The photos below show the distinct abdominal markings of Nemoria bifilata (left) Nemoria bistriaria (left center) Nemoria mimosaria (right center) and Nemoria tuscarora (right).

The form of the antennae, including the presence or absence of sexual dimorphism in male and female antennae, can also be important in distinguishing species. In the genus Synchlora, the antennae are broadly pectinate over the first two-thirds of their length, tapering to a simple antenna in the outer third. (photo, below left). Markings on the legs and the shape of leg segments can be important anatomical features to confirm an identification. In the East, Nemoria bistriaria and Nemoria lixaria both display an oblique whitish band on the anterior surface of the foretibia. In some genera, the hindtibia is extended in a significant extension beyond the joint with the tarsal segment. (photo below center). Species in the genera Dichorda and Nemoria all have two pairs of hindtibial spurs in both sexes (photo below right) while another North American genus in the Nemoriini, Chlorosea, has only one pair of spurs on the hindtibia.