Abstract
This paper is the first in a series on the Lepidoptera of the Sierra Madre Occidental area of Durango, Mexico. The immature stages of eight species of Geometridae are described in detail: Grossbeckia semimaculata Barnes and McDunnough, Semiothisa cyda (Druce), Galenara lallata (Hulst), Glena interpunctata interpunctata (Barnes and McDunnough), Iridopsis sp., Anacamptodes angulata Rindge, Phaeoura kirkwoodi Rindge, and Sicya snoviaria Hulst. Less detailed descriptions or short notes are given for the pierids Colias caesonia (Stoll) and Eucheira socialis Westwood; the arctiids Halisidota propinqua Henry Edwards and Arachnis perotensis Schaus; the noctuids Lichnoptera gulo Herrich-Schaeffer and Lacinipolia eucyria Dyar; a notodontid, Disphragis edwardsi Druce; a lasiocampid, Malacosoma incurvum aztecum (Neumogen); a pyralid, Dioryctria rossi Munroe; and an olethreutid, Petrova albicapitana (Busck).