Ctenichneumon Thomson, 1984
Ctenichneumon is a moderately diverse genus of medium-sized wasps. Most species vary between iridescent blue and plain black. However, there is one abberant species that is entirely light brownish-red (present in at least Utah and California). There are 14 described species and an unknown but not insignificant number of undescribed species in the West.
Ctenichneumon belongs to a group of genera including Ichneumon that all share a longitudinally striate postpetiole. More specifically, Ctenichneumon is a member of the Amblyteles genus-group which includes Diphyus, Eutanyacra, Limerodops ,and Spilichneumon, among others. It is easily differentiated from these related genera based on the typical color pattern described above, but more importantly, by the large, deeply-impressed gastrocoeli and absent thyridia. This combination of traits does not occur in any other Nearctic ichneumonine genus.
Due to the similarity in color, Ctenichneumon may be confused with Coelichneumon and other genera with iridescent blue species such as Platylabus or Patrocloides.
Biology
Palearctic Ctenichneumon spp. have been recorded as parasites of noctuids. There are no recorded rearings of Nearctic species.
Diagnosis
- postpetiole of MS1 longitudinally striate
- female metasomal apex amblypygous
- gastrocoeli well-developed and deep but thyridia absent
- male flagellum with well-developed bristle ridges
- color usually black or iridescent blue