Diptera:Bombyliidae:Anthracini

Black Bee Flies are strong fliers, often found feeding on blossom, flying around dead or fire-blackened trees where mud wasps are building nests

Anthracini larvae are parasites on larvae of other insects. Females lay eggs near a potential host. The first instars are free-living and will find the host within the ground or host nest. Later instars usually feed upon a single host. The pupa is armed with spines.

(reference: http://www.brisbaneinsects.com/brisbane_robbers/Anthracini.htm )