Chromonema heliothidis n. gen., n. sp. (Steinernematidae, Nematoda), a parasite of Heliothis zea (Noctuidae, Lepidoptera), and other insects.

Chromonema heliothidis n. gen., n. sp. is described as an entomophilic nematode of Heliothis zea and other lepidopterous larvae; the diagnosis of the family Steinernermatidae is emended. In most morphological and host-parasite features, this nematode is similar to neoaplectanid nematodes; however, males are different in having a peloderan bursa and straight to slightly curved spicules. Although the infective-stage juveniles only give rise to hermaphrodites, the nematode is heterogonic, with both males and females being produced in the second generation. Parasitized hosts are brick-red in color and luminescent in the dark because of the association of a chromogenic, bioluminescent bacterium with the nematode. The nematode is capable of parasitizing a wide range of insects with lepidopterous larvae being most susceptible.