144 INSECTS. 



It consists of a row of hooks, placed upon the anterior 

 nerve of the hind wing, which play upon the folded- 

 in corresponding edge of the fore wing ; the hooks, 

 sliding along this edge, allow of freedom of motion, 

 although still holding the two wings together. This 

 structure may be well seen in the wings of the Humble 

 Bee when mounted in balsam. 



The sting of the wasp and bee is also a singular 

 organ. In both insects it is much alike, consisting 

 of a sheath, slit up beneath, in which are contained 

 two long setae, or lancets, with bent-back (recurved) 

 teeth near the end. These setae are inserted into 

 the flesh during the act of stinging, and at the same 

 time the poisonous secretion from two glands is 

 forced into the wound, which causes the severe pain 

 resulting from the sting. 



In the wingless neuters of the common ant, attached 

 to the end of the tibia (PI. X. fig. 34 c) is a beautiful 

 pectinate process, somewhat resembling a comb (fig. 

 34 a). 



LEPIDOP'TERA (\67rl$, scale, Tnepov, wing). This 

 Order contains the butterflies and the moths, the 

 entire bodies of which are covered with minute scales. 

 When the insects are handled, these scales adhere to 

 the fingers as a fine dust ; and on pressing a slide 

 against the insects, they may be removed for examina- 

 tion. They consist of a very slender and short quill, 

 by which they are attached, and a flattened plate of 

 various forms (Pl.X. fig. 19, b,f) ; it is, however, ge- 

 nerally narrower near the quill, and expanded towards 

 the free end, where it is often cut into lobes or tooth- 

 like segments. The scales are usually covered with 

 continuous longitudinal lines or ridges, with granules 

 of colouring-matter (pigment) situated between the 

 two thin layers of which the scales consist. In some 

 of them the form is that of a filament, either simple 

 or branched at the end (fig. 19 e), when they resemble 

 minute hairs. In the males of the large white Cab- 



