ORDER HYMENOPTERA: ANTS, BEES, WASPS, ETC. 229 



been observed in three different quarters of the globe to have 

 a predilection for blood-sucking flies of the Tabanid family. 

 The species of Bembex resemble heavy-built wasps, the. 

 " waist " being a constriction and not a long slender stalk ; 

 their colour is black or brown, with sinuous, or V-shaped, 

 yellow, or milky cross-bands on the abdomen ; the head is 

 broad, the eyes are large, and the labrum is usually long and 

 pointed ; the legs are stoutish and spinose, and the tarsi are 

 hairy. The female Bembex makes loose burrows in sand, not 

 troubling to keep the mouth of the burrow open. In each 

 loose cell she deposits an egg and a small provision of dead 

 flies. The larva finishes this supply soon after hatching, and 

 then the mother continues to feed it with fresh-caught flies as 

 birds feed their nestlings. The larva of one species of Bembex 

 is known to live fourteen or fifteen days before pupating, and 

 is believed to consume between fifty and eighty flies. Some 

 species of Bembex are gregarious (not social). One species of 

 Bembex is known to be victimised in turn by a Tachinid fly, 

 which lays its eggs on the prey as it is being carried by the 

 mother to her larva ; the eggs of the Tachinid are thus intro- 

 duced into the nest, and hatching there, the Tachinid larvae 

 play the part of cuckoo, being fed by the Bembex at the 

 expense of her own larva, which at last they may even kill 

 and eat. 



(d) Heterogyna, or Formicidce ; Ants. Ants are dis- 

 tinguished from other Aculeate Hymenoptera by the 

 structure of the stalk or petiole that connects the " thorax " 

 with the " abdomen " ; the one or two segments that compose 

 the petiole are extremely mobile and bear a dorsal node or 

 " scale." The mouth-parts also are peculiar, the maxillae and 

 the labium, and their palps, usually being packed close 

 together so as to give the utmost freedom to the powerful 

 mandibles. The antennae are elbowed. All the ants are 

 social, though with some few species the communities consist 

 of a very small number of individuals. The typical ant- 

 communities are large and are composed of one or more 

 usually winged queens, and of myriads of wingless workers 

 (sterile females), which may be of more than one kind. The 

 communities are lodged in a labyrinth of chambers and 

 galleries near the surface of the ground (ant-hills), or far 



