days of August were ready to emerge as perfect Insects. Thus the whole cycle of metamorphoses is passed through in about eight weeks. This species, though very clever in drilling holes, does not hesitate to appropriate old burrows should they be at hand. Fabre observed that it was also quite willing to save itself labour by forming its cells in hollow reeds of sufficient calibre. We have figured the larva and pupa of this species in the previous volume (p. 170).

Xylocopa chloroptera in E. India selects a hollow bamboo for its nidus; it cements together the pieces obtained in clearing

FIG. 17.-Xylocopa (Koptorthosoma), sp. near flavonigrescens, 8. Sarawak. out the bamboo, and uses them as horizontal partitions to separate the tube into cells. The species is much infested with a small Chalcid of the genus Encyrtus: 300 specimens of the parasite have been reared from a single larva of the bee; two-thirds of the larvae of this bee that Horne endeavoured to rear were destroyed by the little Chalcid.

The most beautiful and remarkable of all the bees are the species of Euglossa. This genus is peculiar to Tropical America, and derives its name from the great length of the proboscis, which in some species surpasses that of the body. The colours in Euglossa proper are violet, purple, golden, and metallic green, and two of these are frequently combined in the most harmonious manner; the hind tibia is greatly developed and forms a plate, the outer surface of which is highly polished, while the margins are furnished with rigid hairs. Very little is known as to the habits of these bees; they were formerly supposed to be

social; but this is doubtful, Bates having recorded that E. surinamensis forms a "solitary nest." Lucas concluded that E. cordata is social, on the authority of a nest containing dozen individuals." No workers

are known. The species of Eulema have a shorter tongue than Euglossa, and in form and colour a good deal resemble our species of Bombus and Apathus.

The group DASYGASTRES includes seven European genera, four being British (Chelostoma being included in Heriades). The ventral surface of the hind body is densely set in the females with regularly arranged hairs, by means of which the pollen is carried. In many of the Dasygastres (Megachile, e.g.) the labrum is very large, and in repose is inflected on to the lower side of the head, and closely applied to the doubled-in tongue, which it serves to protect; the mandibles then lock together out

A

B

а

This group

side the labrum, which is thus completely concealed. includes some of the most interesting of the solitary bees.

The genus Chalicodoma is not found in our own country, but in the South of France there exist three or four species. Their habits have given rise to much discussion, having been described by various naturalists, among whom are included Réaumur and Fabre. These Insects are called mason-bees, and construct nests of very solid masonry. C. muraria is in appearance somewhat intermediate between a honey-bee and a Bombus; it is densely hairy, and the sexes are very different in colour. It is solitary in its habits, and usually chooses a large stone as a solid basis for its habitation. On this a cell is formed, the material used being a kind of cement made by the Insect from the mixture of a

suitable sort of earth with the material secreted by its own salivary glands; the amount of cement used is reduced by the artifice of building small stones into the walls of the cell; the stones are selected with great care. When a cell about an inch

in depth has been formed in this manner, the bee commences to fill it with food, consisting of honey and pollen; a little honey is brought and is discharged into the cell, then some pollen is added. This bee, like other Dasygastres, carries the pollen by means of hairs on the under surface of the body; to place this pollen in the cell the Insect therefore enters backwards, and then with the pair of hind legs brushes and scrapes the under surface of the body so as to make the pollen fall off into the cell; it then starts for

FIG. 19.-Chalicodoma muraria. Greece. a fresh cargo; after a few loads A, Male; B, female.

have been placed in the recep

tacle, the Insect mixes the honey and pollen into a paste with the mandibles, and again continues its foraging until it has about half filled the cell; then an egg is laid, and the apartment is at once closed with cement. This work is all accomplished, if the weather be favourable, in about two days, after which the Insect commences the formation of a second cell, joined to the first, and so on till eight or nine of these receptacles have been constructed; then comes the final operation of adding an additional protection in the shape of a thick layer of mortar placed over the whole; the construction, when thus completed, forms a sort of dome of cement about the size of half an orange. In this receptacle the larvae pass many months, exposed to the extreme heat of summer as well as to the cold of winter. The larvae, however, are exposed to numerous other perils; and we have already related (vol. v. p. 540) how Leucospis gigas succeeds in perforating the masonry and depositing therein an egg, so that a Leucospis is reared in the cell instead of a Chalicodoma.

This Insect has been the object of some of J. H. Fabre's most instructive studies on instinct. Although it is impossible for us here to consider in a thorough manner the various points he has discussed, yet some of them are of such interest and importance as to demand something more than a passing allusion.

We have mentioned that the nest of Chalicodoma is roofed with a layer of solid cement in addition to the first covering with which the bee seals up each cell. When the metamorphoses of the imprisoned larva have been passed through, and the moment for its emergence as a perfect Insect has arrived, the prisoner has to make its way through the solid wall by which it is encompassed. Usually it finds no difficulty in accomplishing the task of breaking through the roof, so that the powers of its mandibles must be very great. Réaumur has, however, recorded that a nest of this mason-bee was placed under a glass funnel, the orifice of which was covered with gauze, and that the Insects when they emerged from the nest were unable to make their way through the gauze, and consequently perished under the glass cover; and he concluded that such insects are only able to accomplish the tasks that naturally fall to their lot. By some fresh experiments Fabre, however, has put the facts in a different light. He remarks that when the Insects have, in the ordinary course of emergence, perforated the walls of their dark prison, they find themselves in the daylight, and at liberty to walk away; when they have made their escape from a nest placed under a glass cover, they, having no knowledge of glass, find themselves in daylight and imprisoned by the glass, which, to their inexperience, does not appear to be an obstacle, and they therefore, he thought, might perhaps exhaust themselves in vain efforts to pass through this invisible obstacle. He therefore took some cocoons containing pupae from a nest, placed each one of them in a tube of reed, and stopped the ends of the reeds with various substances, in one case earth, in another pith, in a third brown paper; the reeds were then so arranged that the Insects in them were in a natural position; in due course all the Insects emerged, none of them apparently having found the novel nature of the obstacle a serious impediment. Some complete nests were then taken with their inmates, and to the exterior of one of them a sheet of opaque paper was closely fastened, while to another the same 1 Souvenirs entomologiques. 4 vols. Paris, 1879 to 1891.

sort of paper was applied in the form of a dome, leaving thus a considerable space between the true cover of the nest and the covering of paper. From the first nest the Insects made their escape in the usual manner, thus again proving that paper can be easily pierced by them. From the second nest they also liberated themselves, but failed to make their way out through the dome of paper, and perished beneath it; thus showing that paper added to the natural wall caused them no difficulty, but that paper separated therefrom by a space was an insuperable obstacle. Professor Pérez has pointed out that this is no doubt due to the large space offered to the bee, which consequently moves about, and does not concentrate its efforts on a single spot, as it of course is compelled to do when confined in its natural cell.

The power of the mason-bee to find its nest again when removed to a distance from it is another point that was tested by Du Hamel and recounted by Réaumur. As regards this Fabre has also made some very valuable observations. He marked some specimens of the bee, and under cover removed them to a distance of four kilometres, and then liberated them; the result proved that the bees easily found their way back again, and indeed were so little discomposed by the removal that they reached their nests laden with pollen as if they had merely been out on an ordinary journey. On one of these occasions he observed that a Chalicodoma, on returning, found that another bee had during her absence taken possession of her partially completed cell, and was unwilling to relinquish it; whereupon a battle between the two took place. The account of this is specially interesting, because it would appear that the two combatants did not seek to injure one another, but were merely engaged in testing, as it were, which was the more serious in its claims to the proprietorship of the cell in dispute. The matter ended by the original constructor regaining and retaining possession. Fabre says that in the case of Chalicodoma it is quite a common thing for an uncompleted cell to be thus appropriated by a stranger during the absence of the rightful owner, and that after a scene of the kind described above, the latter of the two claimants always regains possession, thus leading one to suppose that some sense of rightful ownership exists in these bees; the usurper expressing, as it were, by its actions the idea-Before I