Nest burrows are stocked with a range of Diptera: Brachycera from various families. Nesting biology Nests are dug in sandy soil in level areas exposed to full sun, with nesting often occurring in large aggregations. Nests consist of a single sloping unbranched burrow of 10-15cm in length with a single cell at the bottom, the last part of which may be dug nearly horizontally (Lomholdt 1984). Bembix practices progressive provisioning, females initially stock the nest with a small fly onto which the egg is laid and seal up the entrance. As the larva grows and consumes its meal, larger prey items are brought to the nest, with the female sealing the burrow after each visit. Females may be provisioning a number of nests at the same time. When fully fed the larvae spin tough cocoons incorporating sand grains into the outer wall, which are said to be "strong enough to withstand the maximum pressure between human fingers" (Crompton 1948).