Fig. 303.—A, Eggs of Ascalaphus macaronius. B, Sketch of position of the young larvae of Helicomitus insimulans (?); C, outline of natural size. (After Westwood.)
When the weather is wet or cold the Ascalaphi repose on the stems of grass, with their wings placed in a roof-like manner, with the head downwards, and are then very successful in concealing themselves by the positions they assume, and by sidling round the stems to escape from enemies. Some information as to their metamorphosis has been obtained, though knowledge of this point is far from complete even as regards our European species of the typical genus Ascalaphus. For a long time it was supposed that a larva mentioned by Bonnet in his writings was that of Ascalaphus, but Brauer[[386]] is of opinion that such is not the case, and as he has described the metamorphoses of A. macaronius he is no doubt correct. The eggs (Fig. 303, A), forty or fifty in number, are laid in two parallel rows on the stems of grass. The larvae (Fig. 304, larva of Helicomitus ?) are in general appearance somewhat like those of Myrmeleon; they are carnivorous in their habits, like the ant-lions, and have similar extraordinarily developed mandibles. Efforts to rear the young larvae failed, but they were kept alive for some time by supplying them with Aphidides found on Centaurea jacea. The cocoon is globular, and the change from the nymph state to the imago is made in the cocoon, the structure of the mandibles of the pupa being peculiar, and specially adapted to the purpose of opening the cocoon.[[387]] The larvae of Ascalaphides, although so like the ant-lions in appearance, do not form pitfalls for the capture of their prey, but lurk under leaves on the ground, or under stones; they do not move backwards, but progress forwards in an ordinary manner; the habit of backward movement that we noticed in Myrmeleon being probably correlative with the habit of forming pitfalls. Hagen states[[388]] that the larvae of Ascalaphides and Myrmeleonides, in addition to their peculiarities of form and mandibular structure, are distinguished from those of other Hemerobiidae by the hind legs having the tibia and tarsus united without articulation. Westwood[[389]] has recently given an account of the young larvae of a Ceylonese Ascalaphid of doubtful species, but possibly Helicomitus insimulans; these were observed by Mr. Staniforth Green to have the very peculiar habit of sitting together in a long row on the stem of a plant, with the jaws widely extended and the body of each one covered by the head of the individual next it (Fig. 303, B). The little creatures waited patiently in this position until a fly walked between the mandibles of one of them, then these formidable weapons immediately closed, and did not relax their hold until the fly was sucked dry. If Westwood is correct, the young larva of this species differs much from the adult one, the back of the head being broad and the setigerous processes of the body very much more developed. Nearly thirty genera of Ascalaphides are known.[[390]] In the genus Haplogenius we find an exception to the usual rule that the wings in repose are held in a roof-like manner, it having been noticed by Bates that in the species in question the wings are held expanded as in the dragon-flies.
Fig. 304.—Larva of Helicomitus insimulans (?). (After Westwood.)
Guilding has described[[391]] a very peculiar mode of oviposition on the part of Ulula macleayana in the island of St. Vincent; the eggs are said to be deposited by the female in circles on the extremity of a twig, and nearer the base of this there is placed a kind of barrier to repel intruders. "The female may be seen expelling from her ovary these natural barriers with as much care as her real eggs." Guilding's description was accompanied by drawings of the eggs, barriers and larvae, but unfortunately these were never published, and no further information has been obtained on the subject. Hagen[[392]] suggests that the barriers may be somewhat similar to the long stalks on which the eggs of Chrysopa (Fig. 314) are placed.
Sub-Fam. 3. Nemopterides.—Head more or less produced and beak-like. Hind wings of peculiar form, being elongate and somewhat strap-like.
Fig. 305.—Nemoptera ledereri. Asia Minor. (After Selys.) A, The imago; B, its head seen from in front and magnified.
