The ant-lion is capable of sustaining prolonged fasts. Dufour kept specimens for six months without any food. These Insects are said to give off a peculiar ant-like odour, due, it is thought, to their ant-eating habits. Although no species inhabits Great Britain, yet one is found in Southern Sweden. Introduced specimens get on very well in confinement in our country,[[383]] and would probably flourish at large for some years if they were liberated.
Although the number of known species and genera of Myrmeleonides is considerable—that of the species being now upwards of 300—the members of the small genus Myrmeleon are the only forms that are known to make pits of the kind we have described. Other larvae[[384]] are known similar in general form to the common ant-lion, but they walk forwards in the normal manner, and apparently hunt their prey by lurking in a hidden place and, when a chance occurs, rushing on the victim with rapidity. Brauer has observed this habit in the case of Dendroleon pantherinus in the Prater at Vienna.
Fig. 301.—Upper aspect of head and alimentary canal of Myrmeleon: a, crop; b, stomach; c, free extremities of two Malpighian tubes; c′, terminal common portion of other six tubes; d, coecum; e, spinneret; f, f, muscles for protruding its sheath; g, g, maxillary glands. (After Meinert.)
The most remarkable forms of Myrmeleonides are contained in the genus Palpares. We figure Tomateres citrinus (Fig. 299), an allied genus found in Eastern Africa as far south as Natal. These Insects have conspicuous blotches and marks on their wings. The species of Myrmeleon are similar in form, but are smaller, more feeble, and less ornate in appearance.
Pitfalls, formed in all probability by ant-lions, have been noticed in the Galapagos islands and in Patagonia, though none of the Insects forming them have been found.
Sub-Fam. 2. Ascalaphides.—Antennae elongate, with a knob at the tip; the apical area of the wing with irregular cellules.
Fig. 302.—Ascalaphus coccajus. East Pyrenees.
The sub-family Ascalaphides is not represented by any species in Britain, though Ascalaphus longicornis occurs as far north as Paris. In the mountainous regions of Central and Southern Europe some species of the group form a conspicuous part of the Insect fauna, owing to their bold and active flight; they are predaceous in their habits, and fly about in a hawking fashion somewhat like that of dragon-flies. Some of the larger of the numerous exotic species of the group are very like dragon-flies, but can be distinguished by a glance at the elongate antennae with a knob at the end. The sub-family consists of two groups—Holophthalmi and Schizophthalmi. M‘Lachlan says[[385]]: "The eyes in the Schizophthalmous division are really double, the upper portion overlapping the under; if the upper portion be separated the lower division looks like a small spherical ordinary eye." There appears, however, to be considerable differences in the genera in this respect.