Wilhelm Julius Behrens

“ Compared with the beetles, Diptera or flies take a very prominent position as promoters of cross-fertilization. One great advantage which they have over the former class is their power of free and rapid motion. While the beetles are almost without exception compelled to adopt a slow mode of locomotion, the movements of the flies are among the most rapid known in the insect world. The number of native species of Diptera is very large ”

“ In these species the ventral surface of the abdomen is furnished with long, stiff, retroverted hairs, by means of which the pollen is brushed from the anthers as the insect passes in or out of the flower. The grains get entangled among the hairs, from among which the bee afterward dislodges them by means of its legs.
This contrivance is admirably adapted for obtaining pollen from flowers having a flat corolla, but not for such as have the anthers concealed in a deep tube. Our most highly developed bees (humble-bees, honey-bees, etc.) ”

“ One of the largest and most rapid flying of the Diptera is the humble-bee fly (Bombylius major, Fig. 6) . In this species the proboscis, which is situated on the anterior portion of the head, is of considerable length, so that the insect can reach the honey even when it is secreted some way down the 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 humble-bees do not fall far short of the honey-bees in the assiduity with which they frequent flowers, and they surpass the latter in size and in length of proboscis. Our most common species are the earth humble-bee (Bombus terrestris, Fig. 15) , the garden humble-bee (Bombus hortorum) , the moss-bee (Bombus muscorum) , and the stone-bee (Bombus lapidarius) . Very
similar to the humble-bees in appearance and structure are the hairy-bees, one of which is shown in Fig. 13. They are readily distinguished, however, as we shall presently see, by the formation of the hind-legs. ”

“ Laden with the fruits of its toil, the insect wings its way homeward, and deposits them in the bee-hive.
While our native flowers are many of them entirely dependent on insects for the transference of pollen, the process of cross-fertilization is, in many tropical species, always effected by birds, which visit the flowers on account of their nectar.
In America the humming-birds (Trochilidæ, Figs. 20-22) and in Africa the honey-eaters (Cinnyridæ) are the great promoters of cross-fertilization. ”

“ 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 just considered. The posterior part of the body is mostly distinguished by a number of bright and dark colored bands and specks. ”

“ We have already said that, over and above their high intelligence, bees are remarkable for having certain parts of their body specially modified in connection with the acquiring of honey and pollen. We must therefore further consider the structures concerned in effecting this end, viz., the suctorial apparatus and the apparatus for collecting pollen.
The suctorial apparatus is in most bees developed in very great perfection. In many (Figs. 13-15) the proboscis is of considerable ”

“ The length of the beak varies in accordance with the length of the corolla-tube of the flowers habitually visited by the different species. In the Heliactinus cornutus of Brazil (Fig. 21) it is 1*5 centimetre long, in the Heliothrix aurita of Minas-Geraës in Brazil (Fig. 20) about two centimetres. ”

“ Their flight does not resemble that of any of our native birds, being maintained by rapid vibrations of the wings, which enable them to remain apparently motionless in one spot for a considerable time. ”