THE BEE. 43 



to other uses than that for which organs of flight are 

 usually destined. The wings are, as before stated, 

 four in number, the anterior pair being the largest 

 (PI. II. figs. 1, 4) . They are composed of a double 

 membrane which is covered all over with fine hairs, 

 and stretched out upon what are termed " nervures," 

 or ribs, that ramify between the double fold. (PI. VI. 

 fig. 4.) 



Accompanying the nervures are also to be found 

 a set of vessels for the circulation of air (trachese), 

 and another set for the passage of blood ; and although 

 the nervures are not so numerous in this as in some 

 other insects, they are of a firm consistent nature, 

 giving to the wings that tough membranous texture 

 which characterizes the order (Hymenoptera). 



But you may be disposed to ask why the wings 

 of a Bee should require to be tougher and more re- 

 sisting than those of other insects. This would be a 

 very natural inquiry, and one that we shall seek to 

 answer satisfactorily ; but, before doing so, let us for 

 a moment direct your attention to another feature in 

 connexion with these organs. Supposing it to be 

 necessary that they should ofler great resistance to 

 the atmosphere and present the broadest possible un- 

 broken surface, this object would of course be greatly 

 facilitated if the two pairs of wings could be locked 

 together in such a manner that it would be impossible 

 for a current of air to pass between them. Well, 

 then, without rendering them permanently adherent, 

 which would make it inconvenient for the insect to 



