variable in form, pedicellate in some abnormal forms, but more usually not stalked. The Crabronides (Vespa crabro, the hornet, is not of this subfamily) are wasp-like little Insects, with unusually robust and quadrangular head. They frequently have the hind tibiae more or less thickened, and the clypeus covered with metallic hair. It appears at present that they are specially attached to the temperate regions of the northern hemisphere, but this may possibly be in part due to their having escaped attention elsewhere. In Britain they form the most important part of the fossorial Hymenoptera, the genus Crabro (with numerous sub FIG. 52.-Crabro cephalotes ?. Britain. genera) itself comprising thirty species. The males of some of the forms have the front tibiae and tarsi of most extraordinary shapes. They form burrows in dead wood, or in pithy stems, (occasionally in the earth of cliffs), and usually store them with Diptera as food for the larvae : the wings and dried portions of the bodies of the flies consumed by Crabronides are often exposed to view when portions of old wood are broken from trees. The genus Oxybelus is included by some systematists, but with doubt, in this sub-family; if not placed here, it must form a distinct sub-family. It has the metathorax spinose, and the submarginal and first discoidal cells are not, or are scarcely, separated. Crabro leucostomus has been observed by Fletcher to form cells for its larvae in the soft wood of broken willows: the food stored therein consists of two-winged flies of the family Dolichopodidae. This Crabro is parasitised by an Ichneumonid of the genus Tryphon, and by a two-winged fly of uncertain genus, but belonging to the family Tachinidae. The metamorphoses of Crabro chrysostomus have been briefly described by Verhoeff: the food stored consists of Diptera, usually of the family Syr VOL. VI K phidae; the larva spins an orange-red cocoon, passes the winter therein, and assumes the pupal form in the spring; there is, he says, a segment more in the female pupa than there is in the male. The species of the sub-genus Crossocerus provision their nests with Aphididae, but C. wesmaeli makes use, for the purpose, according to Ferton, of an elegant little fly of the family Tipulidae; according to Pissot this same wasp also makes use of a species of Typhlocyba, a genus of the Homopterous division of Rhynchota. Supposing there to be no mistake as to this latter observation, the choice of Diptera and of Homoptera by the same species indicates a very peculiar habit. Fertonius (Crossocerus) luteicollis in Algeria forms cells at a slight depth in sandy soil, and provisions them with ants. The ant selected is Tapinoma erraticum, and the individuals captured are the wingless workers. The mode of hunting has been described by Ferton; the wasp hovers over one of the ant-paths at a distance of a few millimetres only above the surface, and when an ant that is considered suitable passes, the Fertonius pounces on it, stings it, and carries it off to the burrow; forty or fifty ants are accumulated in a cell, the egg is laid in the heap of victims about one-third of the depth from the bottom; the resulting larva sucks the ants one by one, by attaching itself to the thorax behind the first pair of legs. There is a very interesting point in connection with the habits of this species, viz. that the ants are not only alive, but lively; they have, however, lost the power of co-ordinating the movements of the limbs, and are thus unable to direct any attack against the feeble larva. Ferton thinks there are three generations of this species in a single year. NOTE. In a note on p. 99 we have mentioned the new publication of Mr. and Mrs. Peckham on the habits of Fossores. We may here add that it contains much fresh information on these Insects, together with criticisms of the views of Fabre and others. One of the points most noteworthy is that they have observed Crabro stirpicola working night and day for a period of forty-two consecutive hours. They made experiments on Bembex spinolae with a view of ascertaining whether the female provisions two nests simultaneously; as the result they think this improbable. If the female Bembecid make nests only consecutively, it is clear it must have but a small fecundity. The larval life extends over about fifteen days; and if we allow three months as the duration of life of a female, it is evident that only about six young can be produced in a season. CHAPTER IV HYMENOPTERA ACULEATA CONTINUED DIVISION IV. FORMICIDAE OR ANTS Division IV. Heterogyna or Formicidae Ants. A α b d d The segment, or the two segments, behind the propodeum, either small or of irregular form, so that if not throughout of small diameter, the articulation with the segment behind is slender, and there is great mobility. The trochanters undivided. The individuals of each species are usually of three kinds, males, females and workers; the latter have no wings, but the males and females are usually winged, though the females soon lose the flying organs. They live in communities of various numbers, the majority being workers. The larvae are helpless maggots fed and tended by the workers or by the female. IN ants the distinction between the three great regions of the body is very marked. The abdomen is connected with the propodeum in a peculiar manner, or two segments being detached from the main mass to form a very one C B a FIG. 53-Abdomens of ants. A, Of Camponotus rubripes (Formicides); B, of Ectatomma auratum (Ponerides); C, of Aphaenogaster barbara (Myrmicides). a, Propodeum; b, first abdominal segment forming a scale or node; c, second; d, third abdominal segment. mobile articulation. This is the most distinctive of the characters of ants. The structure and form of these parts varies greatly in the family: and the Amblyoponides do not differ in a marked manner from the Scoliidae in fossorial Hymenoptera. The arrangement of the parts of the mouth is remarkable, and results in leaving the mandibles quite free and unconnected with the other trophi; the mouth itself is, except during feeding, B FIG. 54.--Front of head of Dinoponera grandis. closed completely by the lower lip and maxilla assuming an ascending vertical direction, while the upper hangs down lip hangs and overlaps the lower lip, being closely applied to it; so that in Ponerides the palpi, except the apices of the maxillary pair, are enclosed between the upper and lower lips (Fig. 54, A). In Cryptocerini the palpi are not covered by the closed lips, but are protected by being placed in chinks at the outsides of the parts closing the mouth. The mandibles of ants can thus be used in the freest manner without the other parts of the mouth being opened or even moved. The mandibles close transversely over the rest of the mouth, and when shut are very firmly locked. There are, however, some ants in which the lips remain in the position usual in mandibulate Insects. The antennae, except in the males of some species, have a long basal joint and are abruptly elbowed at its extremity. The eyes and ocelli vary excessively, and may be totally absent or very highly developed in the same species. The winged forms are, however, never blind. The size of the head varies extremely in the same species; it is frequently very small in the males, and largest in the workers. In some ants the worker-caste consists of large-headed and small-headed individuals; the former are called soldiers, and it has been supposed that some of them may act the part of superior officers to the others. It should be clearly understood that there is no definite distinction between soldiers and workers; so that in this respect they are widely different from Termites. The complex mass forming the thorax is subject to great change of structure in the same species, according as the individuals are winged or wingless. The sutures between the dorsal A (notal) pieces are frequently obliterated in the workers, while they are distinct in the males and females, and the pieces themselves are also much larger in size in these sexed individuals. The pro-mesothoracic stigma is apparently always distinct; the meso-metathoracic one is distinct in the male Dorylus, but can scarcely be detected in the winged forms of other ants, owing to its being enclosed within, and covered by, the suture between the two segments: in the workers, however, it is usually quite conspicuous. The posterior part of the thoracic mass, the propodeum or median segment, is of considerable size; no transverse suture between the component pieces of this part can be seen, but its stigma is always very distinct. The peduncle, or pedicel, formed by the extremely mobile segment or segments at the base of the abdomen (already noticed as forming the most conspicuous character of the family), exhibits much ها B FIG. 55.-Oecodoma cephalotes. South America. A, Worker major; B, female after casting the wings. FIG. 56.-Stridulating organ of an ant, Myrmica rubra, var. laevinodis. Sagittal section of part of the 6th and 7th post-cephalic segments. (After Janet.) a, a1, muscles; b, connecting membrane (corrugated) between 6th and 7th segments: c, 6th segment; d, its edge or scraper; e, striate area, or file on 7th segment; f, posterior part of 7th segment; g, cells, inside body; h, trachea. variety. Sometimes the first segment bears a plate or shield called a scale (Fig. 53, A, b); at other times there are two |