The reproductive biology of Euoniticellus intermedius (Reiche) was studied using insects collected in Quiahuixtlan, Veracruz, Mexico, that were kept under controlled environmental conditions (temperature: 26.9 °C ± 0.09; relative humidity: 69.75% ± 1.7; photoperiod: 14D-10N). The reproductive systems of both sexes—similar to those described for other species of Scarabaeinae—are described. Females lay two eggs each day. Their fecundity is 111 ± 15 eggs. The lifespan of this species is 30 to 60 days. Development from egg to imago ranges from 25 to 28 days. The three larval instars are described.