86 INJURIOUS AND USEFUL INSECTS 



the first vertebra, completed into a ring, rotates upon its 

 own centrum, which has been incorporated with the second 

 vertebra. The mesothorax, which bears the first and 

 principal pair of wings, is of enormous relative size in 

 Hymenoptera, as well as in Diptera and Lepidoptera. The 

 metathorax is reduced to a narrow strip, crowded in between 

 the mesothorax and the first abdominal segment, which, as 

 we have seen, is in Hymenoptera fused with the thorax, 

 and lies in front of the narrow waist. The thorax bears 

 two pairs of spiracles, a mesothoracic pair, which is partly 

 concealed by the movable portion of the prothorax, and 

 a metathoracic, . which lies just beneath the root of the fore 

 wing, in the extreme front of the metathorax ; it is not easily 

 seen without breaking up the thorax. Another spiracle, which 

 is the first abdominal, is plainly visible on the side of the first 

 abdominal segment, which forms part of the same mass with 

 the thorax. 



The fore pair of wings are both longer and wider than the 

 hind pair. A peculiar arrangement exists which has the effect 

 of making the two wings of the same side into one, when the 

 .bee flies. Examine the fore edge of the hind wing with a lens. 

 It will be observed that in the inner (proximal) half the stout 

 rib which supports the margin of the wing bears a row of 

 bristles, but where the outer (distal) half begins, these bristles 

 are curved upwards and form hooks, which are arranged in a 

 row, and cease where the wing begins to be rounded off. 

 Next examine the hinder margin of the fore wing. The part 

 which corresponds in position to the row of hooks on the 

 hind wing is folded underneath as a sharp plait. When the 

 wings are at rest the fore wing overlaps the other ; when they 

 are spread for flight, the fore wing glides outwards over the 

 hind one, meeting no resistance until the row of hooks catches 

 the plait; then the two wings become locked together, and 

 act as one, being, however, automatically released whenever 

 they are brought to the resting position. 



The legs of the worker-bee, but not those of the queen or 

 drone, possess a complex adaptation for the collection of 

 pollen.* The first joint of the tarsus of the hind leg is greatly 

 enlarged, and its inner face {i.e. the face which is ordinarily 



* The best account of the bee's legs that I know is given by Cheshire 

 in " Bees and Beekeeping." 



