Larvae of the yellow mealworm T. molitor (L.) and dark mealworm T. obscurus (F.).
The larvae and adults are similar except for coloration with adult dark mealworms being dull black as opposed to dark brown color of the adult yellow species. Both species may be found together.
The mealworms are one of the largest insects which infest stored cereal products. The larvae become full grown (over 1/2 inch long) in about 3 months but continue to feed and molt until winter. After overwintering, the larvae pupate in the spring. There is but one generation each year.
