Fig. 98.—Scolopendra morsitans (S. Europe).
(After Claus.)
The tropical species may attain a length of 10 or even 15 cm. Their bodies are composed of 21 segments, each provided with a pair of jointed legs. They live in shady places, such as woods, hidden under stones, dead leaves, or the bark of old trees. They feed upon small insects, spiders, and larvæ, which they kill with their venom. The latter is secreted by a racemose gland situated at the base of the poison-claws; it escapes by a duct which opens at the apex.
This venom, the physiological study of which was commenced by Dubosq, is an acid, opalescent liquid, hardly miscible with water.
More complete experiments on this subject have been made by A. Briot,[122] who prepared a solution by sectioning the labium and poison-claws, and crushing the whole in physiological salt solution. When injected intravenously into rabbits, it produces immediate paralysis, with coagulation of the blood; subcutaneously it leads to the formation of enormous abscesses, with necrosis of the tissues. Small animals, such as spiders, species of Scutigera, beetles, &c., are very sensitive to it.
The bite of Scolopendridæ is very painful to human beings. In the Tropics such bites often cause somewhat serious results: insomnia, accelerated and intermittent pulse, and local œdema, which usually disappears after twenty-four hours. Well-authenticated fatal accidents have never been recorded (Bachelier,[123] Saulie[124]).
(d) Insects.
A very large number of insects produce acrid or irritant secretions, which serve them as a means of defence, but cannot be considered as true venoms; the species of Meloë (oil-beetles) and Cantharis (blister-beetles), are the most remarkable in this respect.
The Order Hymenoptera is the only one that includes a multitude of species really provided with poison-glands and an inoculatory apparatus.
