So with the rest, so far as I have been able to experiment with them. Each obstinately refuses what is alien to her hunting-preserves, each accepts whatever belongs to them, always provided that the game substituted is much the same in size and development as that whereof the owner has been deprived. Thus the Tarsal Tachytes, an appreciative epicure of tender flesh, would not consent to replace her pinch of young Acridian-grubs with the one big Locust that forms the food of Panzer's Tachytes; and the latter, in her turn, would never exchange her adult Acridian for the other's menu of small fry. The genus and the species are the same, but the age differs; and this is enough to decide the question of acceptance or refusal.
When its depredations cover a somewhat extensive group, how does the insect manage to recognize the genera, the species composing her allotted portion and to distinguish them from the rest with an assured vision which the inventory of her burrows proves never to be at fault? Is it the general appearance that guides her? No, for in some Bembex-burrows we shall find Sphaerophoriae, those slender, thong-like creatures, and Bombylii, looking like velvet pincushions; no again, for in the pits of the Silky Ammophila we shall see, side by side, the caterpillar of the ordinary shape and the Measuring-worm, a living pair of compasses which progresses by alternately opening out and closing; no, once more, for in the storerooms of Stizus ruficornis and the Mantis-hunting Tachytes we see stacked beside the Mantis the Empusa, her unrecognizable caricature.
Is it the colouring? Not at all. There is no lack of instances. What a variety of hues and metallic reflections, distributed in a host of different fashions, appear in the Buprestes that are hunted by the Cerceris celebrated by Leon Dufour. (Jean Marie Leon Dufour (1780-1865) was an army surgeon who served with distinction in several campaigns and subsequently practised as a doctor in the Landes. He attained great eminence as a naturalist. Cf. "The Hunting Wasps": chapter 1; also "The Life of the Spider": chapter 1.--Translator's Note.) A painter's palette, containing crushed gold, bronze, ruby and amethyst, would find it difficult to rival these sumptuous colours. Nevertheless the Cerceris makes no mistake: all this nation of insects, so indifferently attired, represents to her, as to the entomologist, the nation of the Buprestes. The inventory of the Hornet's larder will include Diptera clad in grey or russet frieze; others are girdled with yellow, flecked with white, adorned with crimson lines;others are steel-blue, ebony black, or coppery green; and underneath this variety of dissimilar costumes we find the invariable Fly.
Let us take a concrete example. Ferrero's Cerceris (C. Ferreri, VAN DERLIND) consumes Weevils. Her burrows are usually lined with Phynotomi and Sitones both an indeterminate grey, and Otiorhynchi, black or tan-coloured.
Now I have sometimes happened to unearth from her cells a collection of veritable jewels which, thanks to their bright metallic lustre, made a most striking contrast with the sombre Otiorhynchus. These were the Rhynchites (R. betuleti), who roll the vine-leaves into cigars. Equally magnificent, some of them were azure blue, others copper gilt, for the cigar-roller has a twofold colouring. How did the Cerceris manage to recognize in these jewels the Weevil, the near relative of the vulgar Phynotomus? Any such encounters probably found her lacking in expert knowledge; her race cannot have handed down to her other than very indeterminate propensities, for she does not appear to make frequent use of the Rhynchites, as is proved by my infrequent discovery of them amid the mass of my numerous excavations. For the first time, perhaps, passing through a vineyard, she saw the rich Beetle gleaming on a leaf; it was not for her a dish in current consumption, consecrated by the ancient usages of the family. It was something novel, exceptional, extraordinary. Well, this extraordinary creature is recognized with certainty as a Weevil and stored away as such.
The glittering cuirass of the Rhynchites goes to take its place beside the grey cloak of the Phynotomus. No, it is not the colour that guides the choice.
Neither is it the shape. Cerceris arenaria hunts any medium-sized Weevil. Ishould be putting the reader's patience to too great a test if I attempted to give in this place a complete inventory of the specimens identified in her larder. I will mention only two, which my latest searches around my village have revealed. The Wasp goes hunting on the holm-oaks of the neighbouring hills the Pubescent Brachyderes (B. pubescens) and the Acorn-weevil (Balaninus glandium). What have these two Beetles in common as regards shape? I mean by shape not the structural details which the classifier examines through his magnifying-glass, not the delicate features which a Latreille would quote when drawing up a technical description, but the general picture, the general outline that impresses itself upon the vision even of an untrained eye and makes the man who knows nothing of science and above all the child, a most perspicacious observer, connect certain animals together.
In this respect, what have the Brachyderes and the Balaninus in common in the eyes of the townsman, the peasant, the child or the Cerceris?
Absolutely nothing. The first has an almost cylindrical figure; the second, squat, short and thickset, is conical in front and elliptical, or rather shaped like the ace of hearts, behind. The first is black, strewn with cloudy, mouse-grey spots; the second is yellow ochre. The head of the first ends in a sort of snout; the head of the second tapers into a curved beak, slender as a horse-hair and as long as the rest of the body. The Brachyderes has a massive proboscis, cut off short; the Balaninus seems to be smoking an insanely long cigarette-holder.
