Key to the families of adult male Strepsiptera found in USA and Canada

1. Mandibles absent..................................................................................... Corioxenidae

– Mandibles present ........................................................................................................ 2

2. Legs with 2 tarsomeres ............................................................................... Elenchidae

– Legs with 3–4 tarsomeres ............................................................................................. 4

3. Legs with 3 tarsomeres; antennae 6–7 segmented with lateral flabella on 3rd, 3rd–4th,

3rd–6th, or 3rd–7th segments ................................................................... Halictophagidae – Legswith4 tarsomeres;antennae4–7segmentedwithlateralflabellumon3rd segmentonly ....................................................................................................................................... 5 4. Antennae 4–6 segmented with broad flat flabella; metathorax with spoon­shaped subalar sclerite ................................................................................................... Stylopidae

– Antennae 7 segmented with narrow, rounded segments; metathorax without spoonshaped subalar sclerite........................................................................ Myrmecolacidae