Our insect of the week is Promachus hinei Bromley, 1931 [DIPTERA: Asilidae]. It is a member of the same family we examined last week (the genus Laphria). Adult robber flies are often fast and loud. They capture other flying insects. This species often hangs from branches waiting for prey to pass by. As with other adult robber flies, it pierces the insect prey and injects fluids which immobilize and dissolve organs and muscles. The fly then drinks the fluid with the same proboscis.

Adults are of minimal threat to humans. They will try to avoid us and will not bite unless handled. In central Illinois, adults are observed from July through September. The specimen in this photograph was collected by our former member, Gordon Adams in August, 1962 (Peoria County).