sand wasps, put away a store of insects or spiders, partially paralyzed, as a provision for the grub till it reaches the pupa state; it actually supplies the grub with fresh-caught insects as long as food is required, killing the prey it captures outright, and bringing it in to its young; so that its habits, in this particular, are more bird- than wasp-like.
The wasp lays its solitary egg at the extremity of a hole it excavates for itself on a bare hard piece of ground, and many holes are usually found close together. When the grub--for I have never been able to find more than one in a hole--has come out from the egg, the parent begins to bring in insects, carefully filling up the mouth of the hole with loose earth after every visit. Without this precaution, which entails a vast amount of labour, I do not believe one grub out of every fifty would survive, so overrun are these barren spots of ground used as breeding-places with hunting spiders, ants, and tiger-beetles. The grub is a voracious eater, but the diligent mother brings in as much as it can devour. I have often found as many as six or seven insects, apparently fresh killed, and not yet touched by the pampered little glutton, coiled up in the midst of them waiting for an appetite.
The Monedula is an adroit fly-catcher, for though it kills numbers of fire-flies and other insects, flies are always preferred, possibly because they are so little encumbered with wings, and are also more easily devoured. It occasionally captures insects on the wing, but the more usual method is to pounce down on its prey when it is at rest. At one time, before I had learnt their habits, I used
164 The Nauiralist in La Plata.
frequently to be startled by two or three or more of these wasps rushing towards my face, and continuing hovering before it, loudly buzzing, attending me in my walks about the fields. The reason of this curious proceeding is that the Monedula preys largely on stinging flies, having learnt from experience that the stinging fly will generally neglect its own safety when it has once fastened on a good spot to draw blood from. When a man or horse stands perfectly motionless the wasps take no notice, but the moment any movement is made of hand, tail, or stamping hoof, they rush to the rescue, expecting to find a stinging fly. On the other hand, the horse has learnt to know and value this fly-scourge, and will stand very quietly with half a dozen loud Avasps hovering in an alarming manner close to his head, well knowing that every fly that settles on him will be instantly snatched away, and that the boisterous Monedula is a better protection even than the tail--which, by the way, the horse wears very long in Buenos Ayres.
I have, in conclusion, to relate an incident I onco witnessed, and which does not show the Monedula in a very amiable light. I was leaning over a gate watching one of these wasps feeding on a sunflower. A small leaf-cutting bee was hurrying about with its shrill busy hum in the vicinity, and in due time came to the sunflower and settled on it. The Monedula became irritated, possibly at the shrill voice and bustling manner of its neighbour, and, after watching it for a few moments on the flower, deliberately rushed at and drove it off. The leaf-cutter quickly returned, however--for bees
A noble Wasp. 165
are always extremely averse to leaving a flower unexplored--but was again driven away with threats and demonstrations on the part of the Monedula. The little thing went off and sunned itself on a leaf for a time, then returned to the flower, only to be instantly ejected again. Other attempts were made,