hairs. Certain other structures entering into the formation of the mouth (e. g., the lip, A, the mandible, D, and the maxillæ, C C) almost equal it in length. The cone-fly (Rhingia rostrata), in common with
Fig. 11.—Structure or the Mouth of the Diptera. I, humble-bee fly; II-IV, cone-fly. II, aide view of head, with the proboscis coiled; III, do., the proboscis beginning to uncoil; IV, do., completely uncoiled. E, eye; F, antennæ; S, beak; T T, palpi; B, extremity of proboscis; A, lip; D, mandible; C C, maxillæ. many other broad-headed flies, possesses the power of coiling up its proboscis, the length of which is about twelve millimetres (Fig. 11, II-IV). That anterior portion of the cone-fly's head (II) is prolonged forward so as to form a sort of beak (S). When not in use, the proboscis is kept coiled up beneath this prolongation. When required, the extremity of the proboscis (B III) is first inclined downward, and the organ is next suddenly shot out to its full length. When fully extended the proboscis projects far beyond the beak-like anterior portion of the head (IV). The extraction of the honey is effected by means of the cleft tip (B). The cleft extremity is used in sucking.
We have already seen that many flowers are exclusively visited by Lepidoptera, their honey not being within the reach of insects belonging to any other order. Such, for instance, are honeysuckle and privet. Very few flowers, however, are frequented solely by Diptera; for the length of the proboscis, even in those Diptera in which it is best developed, is attained, if not surpassed, by many of the Hymenoptera (humble-bees, honey-bees, etc.). The latter class, therefore, share with the Diptera the privilege of frequenting certain species of flowers. We shall now pass on to consider them for a little.
Of all insects the Hymenoptera (bees and wasps) are, on account both of their physical structure and their peculiar instincts, the best adapted for the task of extracting and collecting honey from flowers. The species comprised in this order, and more especially the bees, are all characterized by a superior share of intelligence, not only as honey-hunters, but in many other respects. Their mode of living together in large, well-ordered communities, presided over by a queen, has long been a subject of marvel and of study. Out of the wax, which exudes at the joints of the abdominal segments of their bodies, they construct a "comb," consisting of a number of united cells. The cells when finished are filled with honey or "bee-bread," a substance composed of a mixture of honey and pollen. This bee-bread forms the food upon which the young larvae are reared.
The bees are the greatest promoters of cross-fertilization, not only among the Hymenoptera, but among all insects whatsoever.
Over two hundred species of our native bees (Apidæ) are known as frequenting flowers, the most familiar being the common honey-bee
