none PYRALIDAE-; HYMENOPTERAN-PARASITES; Apanteles deplanatus; Parasite distribution & host range records; MEXICO-; Hymenopteran parasite distribution & host range records Apanteles deplanatus; LEPIDOPTERAN-HOSTS; Pyralidae; Parasite distribution & host range records; MEXICO-; New distribution & lepidopteran host range records Apanteles deplanatus Muesebeck is a gregarious endoparasite of Diatraea considerata (Heinrich) from sugarcane and Diatraea magnifactella Dyar from sugarcane and corn in southern Mexico. Apanteles deplanatus was not reared from the stalkboring pyralids Diatraea grandiosella Dyar, Diatraea lineolata (Walker), Diatraea muellerella Dyar & Heinrich, Diatraea saccharalis (F.), Elasmopalpus lignosellus Zeller, Eoreuma loftini (Dyar), or Xubida rutubella Schaus collected from the same agricultural habitats as the pyralid hosts that were successfully parasitized by A. deplanatus. Field-collected middle-to late-instar host larvae produced parasites; small hosts (first two larval instars) did not produce A. deplanatus. Average brood size was 107 individuals and ranged from 35 to 204. Overall, 85% of a brood was female, although some broods were gt 87% male. The number of female progeny was correlated with brood size, but the number of male progeny was independent of brood size averaging 12 males per brood. Apanteles deplanatus was known previously from the Mexican states of Jalisco and Nayarit; its known range is now expanded across southern Mexico to include the states of Colima, Michoacan, Morelos, Puebla, and Veracruz. Natural mortality of D. considerata and D. magnifactella in corn and sugarcane could be enhanced by expanding the distribution of A. deplanatus to coincide with the distribution of its hosts. Possibilities for colonizing A. deplanatus for biological control of noncoevolved stalkborers is discussed.