Recorders of descriptions, you who, under the scrupulous eye of the magnifying-glass, specify the shapes and establish the identity of the animal species, before you give names and surnames to your impaled insects, pray, pray inquire a little [[129]]into their manner of life. By so doing, you will see things more clearly, you will avoid much detestable nonsense, and you will spare the novice such doubts as those which obsess him when he finds himself obliged to label a Weevil inhabiting the vine-branches as a Rhynchites of the Birch. We are ready to excuse cacophonous syllables and grating consonants; but we reject with exasperation a name that misrepresents the facts.
In her work the Vine-weevil pursues the same method as the Poplar-weevil. The leaf is first pricked with the rostrum at a point on the stalk, which checks the flow of the sap and makes the edges of the faded leaf pliable. The rolling begins at the angle of one of the lower lobes, with the smooth, green upper surface inside and the downy, strongly-veined lower surface outside.
But the great size of the leaf and its deeply indented outline hardly ever allow of regular work from one end of the leaf to the other. Over and over again, sudden folds occur and alter the direction of the rolling, leaving now the green and now the downy surface outside, without any appreciable design, as though by chance. The poplar-leaf, with its simple form and its moderate size, yields an elegant cylinder; the vine-leaf, with its cumbersome width and complicated outline, produces a shapeless cigar, an untidy bundle.
This is not due to defective talents, but to the difficulty of manipulating and controlling a leaf [[130]]of this kind. The mechanical method, indeed, is the same as that practised on the poplar-leaf. With three legs here and three legs there on the edges of the fold, the Bécaru obtains a purchase on one side and tugs and strains on the other.
Like her rival cigar-maker, she works backwards, keeping her eyes upon the part which, folded that moment and still unset, may require immediate touching up. The product is thus watched until it gives proof of its stability.
Like the other, she too seals the denticulations of the final layer by pressing them with her rostrum. Here there is no sticky secretion oozing from the edges of the leaf, but there is a downy fluff whose fibres get entangled and cause adhesion. On the whole, therefore, the method employed by the two Rhynchites is the same.
Nor do their domestic habits differ. While the mother is patiently rolling her cylinder, the father remains close at hand, on the same leaf. He looks on. Next, he comes running along in a hurry, takes his stand in the crease and kindly lends the assistance of his grappling-irons. But he again is not a very diligent helper. His brief collaboration is a pretext to tease the worker and achieve his ends by sheer persistence.
He retires satisfied. Let us watch him. Before the roll is finished, we shall see him return many times, inspired by the same intentions, which are rarely scorned. I need not insist further on these [[131]]pairings, which are repeated indefinitely and run counter to the classic data on one of the nicest points of insect physiology. To impress the seal of life upon the hundreds of eggs of the mother Bombyx,[1] or the thirty thousand or more of the mother Bee, the father exerts only one direct intervention. The Weevil claims the privilege of intervening for almost every egg. I leave the curious problem to the experts.
Let us unroll a recently-made cigar. The eggs, fine, amber-coloured beads, are scattered, one by one, at very different depths in the spiral. As a rule, I find several, from five to eight. The multiplicity of fellow-feasters, in both the rolled poplar-leaf and the rolled vine-leaf, bears witness to extreme frugality.
The two leaf-rollers are quickly hatched: the grub is born in five or six days’ time. Then the observer begins to be faced with the same difficulties that beset a prentice hand in the rearing of larvæ; and these difficulties are all the more exasperating in that there was nothing to predict them. The course to be followed here seems indeed so very simple.