I install three species of Clythræ under wire-gauze covers, each with a bed of sand and a bottle of water containing a few young ilex-shoots, which I renew as and when they fade. All three species are common on the holm-oak: they are the Long-legged Clythra (C. longipes, FAB.), the Four-spotted Clythra (C. quadripunctata, LIN.), and the Taxicorn Clythra (C. taxicornis, FAB.).
I set up a second menagerie with some Cryptocephali, who are closely related to the Clythræ. The inmates are the Ilex Cryptocephalus (C. ilicis, OLIV.), the Two-spotted Cryptocephalus (C. bipunctatus, LIN.) and the Golden Cryptocephalus (C. hypochoeridis, LIN.), who wears a resplendent costume. For the first two I provide sprigs of ilex; for the third, the heads of a centaury (Centaurea aspera), which is the favourite plant of this living gem.
There is nothing striking in the habits of my captives, who spend the morning very quietly, the first five browsing on their oak-leaves and the sixth on her centaury-blooms. When the sun grows hot, they fly from the bunch of leaves in the centre to the wire trellis and back from the trellis to the leaves, or wander about the top of the cage in a state of great excitement.
Every moment couples are formed. They pester each other, pair without preliminaries, part without regrets and begin elsewhere all over again. Life is sweet; and there are enough for all to choose from. Several are persistent. Mounted on the back of the patient female, who lowers her head and seems untouched by the passionate storm, they shake her violently. Thus do the amorous insects declare their flame and win the consent of the hesitating fair.
The attitude of the couple now tells us the use of a certain organic detail peculiar to the Clythra. In several species, though not in all, the males' fore-legs are of inordinate length. What is the object of these extravagant arms, these curious grappling-irons out of all proportion to the insect's size? The Grasshoppers and Locusts prolong their hind-legs into levers to assist them in leaping. There is nothing of the sort here: it is the fore-legs which are exaggerated; and their excessive length has nothing to do with locomotion. The insect, whether resting or walking, seems even to be embarrassed by these outrageous stilts, which it bends awkwardly and tucks away as best it can, not knowing exactly what to do with them.
But wait for the pairing; and the extravagant becomes reasonable. The couple take up their pose in the form of a T. The male, standing perpendicularly, or nearly, represents the cross-piece and the female the shaft of the letter, lying on its side. To steady his attitude, which is so contrary to the usual position in pairing, the male flings out his long grappling-hooks, two sheet-anchors which grip the female's shoulders, the fore-edge of her corselet, or even her head.
At this moment, the only moment that counts in the adult insect's life, it is a good thing indeed to possess long arms, long hands, like Clythra longimana and C. longipes, as the scientific nomenclature calls them. Although their names are silent on the subject, the Taxicorn Clythra and the Six-spotted Clythra (C. sexmaculata, FAB.) and many others also have recourse to the same means of equilibrium: their fore-legs are utterly exaggerated.
Is the difficulty of pairing in a transversal position the explanation of the long grappling-irons thrown out to a distance? We will not be too certain, for here is the Four-spotted Clythra, who would flatly contradict us. The male has fore-legs of modest dimensions, in conformity with the usual rules; he places himself crosswise like the others and nevertheless achieves his ends without hindrance. He finds it enough to modify slightly the gymnastics of his embrace. The same may be said of the different Cryptocephali, who all have stumpy limbs. Wherever we look, we find special resources, known to some and unknown to others.