INSECT FERTILIZATION OF FLOWERS. 



599 



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 Empidos, (Fig. 7) are easily distinguished by the peculiar for- 

 mation 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 Syrphidce 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. T.Empis livida (after Meigen), 

 four times enlarged. Fig. %.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 Syrjokus (Fig. 8), the allied Eris- 

 talis tenax and arbustorum (Fig. 10), and the cone-fly (Mhingia ros- 

 trata, 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 

 consists of a suctorial proboscis, re- 

 sembling 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 UmbelUferce 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, 

 Syrphidce, Empidce, 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 



Fig. 9. Fig. 10. 



Fig. 9. Cone-fly {Rhingia roslrata), natural 

 size. Fig. 10. Eristalis arbustorum, nat- 

 ural size. 



