Synonyms and other taxonomic changes
Symmerista Hübner, (1821)
Adults of species in the genus Symmerista are believed to be indistinguishable, except by examination of the genitalia. Fortunately, males can be recognized, without dissection, by examining the 8th sternite. This is the hard cuticle on the ventral surface of the last segment of the abdomen. The technique is briefly explained in Wagner’s Caterpillar book (p 21), combine this with brushing the scales of the last sternite (8th). S. leucitys has a deep, narrow emargination, whereas in the other 2 eastern species the emargination is shallower and wider.
All the images to species in the Guide, except for those identifed by the 8th sternite or genitalia, are more likely to be incorrect than correct.
Comparison of albifrons, canicosta and leucitys - 8th sternite
The 8th sternite of S. albifrons and leucitys are similar in the overall view, the sides create a U-shaped opening with the upper, lateral edges. In leucitys, there are conspicuous "flanges" along the inner margin and the mesial excavation is small. In canicosta, the upper edges angle outward, with the corner (just above the mesial excavation) projecting inward.
for location of 8th sternite.
genitalia dissection (phallus - apex of the large bilobed process greatly exceeds the apex of the small simple process in albifrons whereas in leucitys the two apexes are subequal)
Covell, p. 332, plate 43 #2 (1)
Wagner, Caterpillars of Eastern Forests
, p. 54 (2)
Wagner, Caterpillars of Eastern North America
, pp.317-318--photos of adults (specimen) and caterpillars, S. canicosta and S. leucitys, discussion of identification issues (3)