Page:Popular Science Monthly Volume 27.djvu/619

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INSECT FERTILIZATION OF FLOWERS.
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corolla-tube. The manner in which Bombylius hovers over a flower while extracting the honey closely resembles that already described as characteristic of the moths among the Lepidoptera.

The Empidæ, (Fig. 7) are easily distinguished by the peculiar formation of the head and proboscis. The latter is not directed forward, but almost perpendicularly downward, and the head itself is round; the whole thus bearing some resemblance to the long-beaked head of a crane. Many of the Syrphidæ are also honey-suckers. In structure they resemble the common house-fly more than the Diptera we have

Fig. 6. Fig. 7. Fig. 8.
Fig. 6.—Humble-bee Fly(Bombylius major), natural size. Fig. 7.Empis livida after Meigen), four times enlarged. Fig. 8.Syrphus, natural size.

just considered. The posterior part of the body is mostly distinguished by a number of bright and dark colored bands and specks. As typical examples we may mention the large Syrphus (Fig. 8), the allied Eristalis tenax and arbustorum (Fig. 10), and the cone-fly (Rhingia rostrata, Fig. 9). The latter may easily be recognized by its peculiar proboscis, which is kept coiled up under a small conical projection on the anterior part of its head. The sucking apparatus of the Diptera Fig. 9.Fig. 10.
Fig. 9.—Cone-fly (Rhingia rostrata), natural size. Fig. 10.Eristalis arbustorum, natural size.
consists of a suctorial proboscis, resembling in a general way that of the common house-fly. It is tubular, short and thickened at its extremity, so as to form a disk, upon which are furrows and hairs. It is by means of this disk that the honey is taken up. The proboscis of the Diptera being almost always short and blunt, they can only extract honey from such flowers as have an open corolla. Insects of this order, then, need only be sought for on flat flowers, and there indeed they may be seen on any sunny day, rapidly creeping about, and greedily imbibing the nectar. The Umbelliferæ are special favorites with them, the nectar being found on the disk in the center of the flower, which can very easily be reached. The Diptera are never found on flowers with long corolla-tubes. Only such forms as the humble-bee flies, Syrphidæ, Empidæ, and a few others, have a proboscis large enough to enable them to obtain honey from flowers of slightly tubular form. The proboscis of Bombylius (Fig. 11, I) is about one centimetre long. It is strong and stiff, cleft at the extremity, B, and thickly beset with