Synonyms and other taxonomic changes
Archiearis infans (Möschler, 1862)
Brephos infans Möschler, 1862
Explanation of Names
INFANS: a Latin word meaning "an infant"; refers to the adult's early emergence from a pupa in the spring, and is the basis for the common names The Infant and First-born Geometer
The only species in this genus in North America.
Adult: forewing mottled brown with prominent white AM and PM patch at costa; AM patch sometimes extends as a band to anal margin; hindwing bright orange with variably developed black median and marginal bands; black patch extends from wing base to median area below discal cell; sexes similar
subspecies A. i. oregonensis, described from Port Orford, Oregon, is larger, paler, and occurs from southern BC to California.
Alaska to Newfoundland, plus northern United States, south in the east to New Jersey, south in the west to California.
Open wooded areas containing birch and alder.
The main flight period is March to May but have been recorded through July.
The larvae feed on leaves of birch, alder, poplar, willow; larvae that hatch before leaves are available in early spring may feed on flower catkins of the host tree.
One generation per year; overwinters as a pupa.
Adults may be seen flying in open woodlands on warm sunny days in early spring. They are fast fliers and normally difficult to capture, but occasionally sip moisture from damp sand or mud puddles; Song Sparrows have been observed to take advantage of this behavior to prey on the moths (Newman & Donahue 1967).
In the far west, they are superficially similar to Dasyfidonia avuncularia
, which has two well-defined continous black bands across hindwing, not patchy and broken as in A. infans
In the Tiger Moth
family, the highly variable Leptarctia californiae
might sometimes look very similar.
In the Crambid Snout Moth
family, Pyrausta dapalis
can look very similar.
Powell, J.A. & P.A. Opler, 2009. Moths of Western North America
. University of California Press, p. 204.; pl. 27, fig. 15. (1)
live adult image
(Cindy Mead, Michigan)
presence in California; list
(U. of California at Berkeley)