Look at this one, striped black, white and red, with the figure of a clumsy, hairy Ant. She explores the slope on foot, inspects every nook and corner, sounds the soil with her antennae. She is a Mutilla, the scourge of the cradled grubs. The female has no wings, but, being a Wasp, she carries a sharp poniard. To novice eyes she would easily pass for a sort of robust Ant, distinguished from the common ruck by her garb of staring motley. The male, wide-winged and more gracefully shaped, hovers incessantly a few inches above the sandy expanse. For hours at a time, on the same spot, after the manner of the Scolia-wasp he spies the coming of the females out of the ground. If our watch be patient and persevering, we shall see the mother, after trotting about for a bit, stop somewhere and begin to scratch and dig, finally laying bare a subterranean gallery, of which there was nothing to betray the entrance; but she can discern what is invisible to us. She penetrates into the abode, remains there for a while and at last reappears to replace the rubbish and close the door as it was at the start. The abominable deed is done: the Mutilla's egg has been laid in another's cocoon, beside the slumbering larva on which the newborn grub will feed. Here are others, all aglitter with metallic gleams: gold, emerald, blue and purple. They are the humming-birds of the insect-world, the Chrysis-wasps, or Golden Wasps, another set of exterminators of the larvae overcome with lethargy in their cocoons. In them, the atrocious assassin of cradled children lies hidden under the splendour of the garb. One of them, half emerald and half pale-pink, Parnopes carnea by name, boldly enters the burrow of Bembex rostrata at the very moment when the mother is at home, bringing a fresh piece to her larva, whom she feeds from day to day. To the elegant criminal, unskilled in navvy's work, this is the one moment to find the door open. If the mother were away, the house would be shut up; and the Golden Wasp, that sneak-thief in royal robes, could not get in. She enters, therefore, dwarf as she is, the house of the giantess whose ruin she is meditating; she makes her way right to the back, all heedless of the Bembex, her sting and her powerful jaws. What cares she that the home is not deserted? Either unmindful of the danger or paralysed with terror, the Bembex mother lets her have her way. The unconcern of the invaded is equalled only by the boldness of the invader. Have I not seen the Anthophora-bee, at the door to her dwelling, stand a little to one side and make room for the Melecta to enter the honey-stocked cells and substitute her family for the unhappy parent's? One would think that they were two friends meeting on the threshold, one going in, the other out!