FLIGHT OF INSECTS. 



315 



Although the greater number of insects have four 

 wings, there are many, such as the common house 





(163) have been engraved. " The sting of this bee (a) is formed of 

 two portions placed laterally together, but capable of being sepa- 

 rated. The point (p) is directed a little upwards, and is a little 



curved ; the barbs, (seen still more 

 highly magnified at q), are about 

 six in number, and are placed on 

 the under surface, and their points 

 directed backwards. At the base 

 of the sting, (e), there is a semicir- 

 cular dilatation, apparently intended 

 to prevent the instrument from being- 

 thrust too far out of the sheath 

 , (shown separately at v), in which it 



^""'i ^% moves : it has also a long tendon, 



to which the muscles are attached. 

 It is between these plates, when 

 approximated, that the poison flows 

 from the orifice of the somewhat 

 dilated extremity of the poison duct, 

 (d), which comes from the anterior 

 part of the poison bag (b). This 

 bag is of an oval shape, and is not 

 the organ which secretes the poison, 

 but merely a receptacle for contain- 

 ing it ; for it is conveyed into this 

 bladder by means of a long convo- 

 luted vessel (c), which receives it from the secreting organs (s). 

 These ors:ans consist of two somewhat dilated vessels resembliuir 

 ccsca, but which have each a slender secretory vessel extending from 

 them. The sting moves in a tubular sheath (v), which is open at 

 its base and along its upper surface, as far as the part where the 

 sting is prevented from being thrust out any farther. The muscles, 

 which move the sheath, are distinct from those of the sting, and are 

 attached to an elongated and curved part on each side of its base,, 

 and to an arched and moveable part which is apparently articulated 

 with it. Swammerdam has delineated these parts as coeca in hi& 

 dissection of the common hive bee, but has not noticed the secretory 

 vessels. The sting of the hive-bee resembles that of the Anthopliora 

 7'etusa." 



