Not an hour after this episode I was treated to another of even more interest. As I took my seat upon the door-step I started into flight a big black wasp, upon whose doings I had evidently been intruding.
This wasp was much larger than the one just described, being about an inch in length. Its wings were pale brown and its body jet-black, with sundry small yellowish spots about the thorax. But its most conspicuous feature, and one which would ever fix the identity of the creature, was the long, slender, wire-like waist, occupying a quarter of the length of its entire body.
In a moment or two the wasp had returned, and stood at the mouth of the shallow pit. Eying me intently for a space, and satisfied that there was nothing to fear, she dived into the hollow and began to excavate, turning round and round as she gnawed the earth at the bottom, and shovelling it out with her spiked legs. Now and then she would back out of the burrow to reconnoitre, and her alert attitude at such times was very amusing—her antennæ drooping towards the burrow and in incessant motion; the abdomen on its long wire stem bobbing up and down at regular intervals, accompanied by a flipping motion of the wings; the short fore legs, one or both, upraised with comical effect.
Black Digger-wasp
As the tunnel was deepened a new method of excavation was employed. It has now reached a depth of an inch, only the extremity of the insect's body appearing, and the two hindermost legs clinging to surrounding earth for purchase. The deep digging is now accompanied by a continual buzzing noise, resembling that produced by a bluebottle fly held captive between one's fingers. At intervals of about ten or fifteen seconds the wasp would quickly back out of the burrow, bringing a load of sand, which it held between the back of the jaws and its thorax, sustained at the sides by the two upraised fore legs. After a moment's pause with this burden, the insect would make a sudden short darting flight of a foot or more in a quick circuit, hurling the sand a yard or more distant from the burrow. At the end of about fifteen minutes the burrow was sunk to the depth of an inch and a half, the wasp entirely disappearing, and indicated only by the continuous buzzing.
At this time, the luncheon hour having arrived, I was obliged to pause in my investigations, and in order to be able to locate the burrow in the event of its obliteration by the wasp before my return, I scratched a circle in the hard dirt, the hole being at its exact centre.
Black Digger-wasp and His Victim, Showing the Egg of the Wasp Attached
Upon my return, an hour later, I was met with a surprise. The ways of the digger-wasps of various species were familiar, but I now noted a feature of wasp-engineering which indeed seems to await its chronicler, as I find no mention of it by the wasp-historians.