not it is really a scorpion: the bare suspicion of a sting is quite enough to warn it off from interfering with any doubtful customer. Moreover, in the second place, even those birds or men who have never seen a scorpion at all are yet sure to be alarmed when an insect sticks up its forked tail menacingly, and shows fight, instead of skulking or flying away. As a general rule, if any animal makes signs of resistance, we take it for granted he has adequate arms or weapons to resist with: and so this mere dumb-show of being a sort of scorpion proves quite sufficient to protect the Devil's Coach-horse from the majority of his enemies. I ought to add that while our beetle thus frightens larger enemies, he is actively and offensively objectionable to small ones. The main use of his tail, indeed, is for folding away his wings, much as the earwig folds hers by aid of her pincers. But the Devil's Coach-horse makes it serve a double purpose. For he has a couple of yellow scent-glands in his tail, which secrete an unpleasant and acrid aromatic substance. These scent-glands are protruded in No. 4: you can just see them at the tip of the tail; and if the annoyance to which the beetle is subjected seems to call for their intervention, a drop of the volatile body they distil is set free, and is at once discharged in the face of the enemy. Such a manoeuvre is in essence like that of the skunk: it is defence by means of a nasty odour, and it occurs not only in the Coach-horse's case, but also among a number of beetles and other insects. The odd little creatures known as Bombardier Beetles are still quainter in their habits: they carry the last-mentioned mode of defence to an even greater pitch of perfection. For, like miniature artillery-men, they actually fire off a regular volley of explosive gas in the faces of their pursuers. The gas is secreted as a liquid; but it is very volatile, and it vaporizes at once on contact with the air, so as to form a small, white cloud of pungent smoke, resembling in its effects nitric acid. Our native English species of Bombardier roams about in large flocks or regiments: and when one member of a clan is disturbed, all the other beetles of the company let off their artillery at once, so that the scattered volley has something the appearance of platoon firing. The chief enemy of the Bombardiers is a much larger and very handsome carnivorous beetle known as Calosoma. When this insect tiger hunts down a single Bombardier, and has almost caught him, the fugitive waits till his pursuer is quite close, and then salutes him with a discharge of fire-arms: the pungent gas gets into the Calosoma's eyes and mouth and distracts him for a moment; and the Bombardier escapes in the midst of the confusion thus caused, under cover of the cloud he himself has exploded. That is the most highly evolved mode of defence of which I know among the British insects.