ABSTRACT
The life cycle, morphology, and bionomy of Photinusextensus Gorham, 1881, an endemic species of Mexico, are described. Redescriptions of adults (male and female) are also presented. Larvae were reared to the adult stage from eggs laid by females collected at the El Pedregal de San Ángel Ecological Reserve, south of Mexico City. The activity period of adults of P.extensus begins at the end of July and finishes by the end of August. Females lay between 3 and 198 eggs. Larvae hatch from the eggs after a period of 11 to 71 days, undergo 6 larval instars and a pupal stage in an annual cycle. Morphological characters of the sixth larval instar of P.extensus are compared with those of several other genera assigned to the tribe Photinini. Knowledge of the natural history of firefly larvae is relevant since most species do not feed as adults and therefore depend on resources acquired during the larval stage.
