EXTERNAL STRUCTURE OF INSECTS. 3o 



enclosed in its sheath and folded close under the 



breast, will- he easily seen in the first hive or humble 



bee the reader may examine ; and, if the bee has not 



been so long killed as to have 



become stiff, all the parts of 



the organ can be opened out 



and displayed by placing a needle 



below the tongue and drawing it 



forward. 



In some bees the labium is com- 

 paratively short, and in different 

 genera cleft or acute, as will be 

 described in a later chapter. 



With the bees we come to the 



. ' . _ i- ' - n Profile of Neuter Hive Bee, 



end of the first division ot in- W uh the tcngue folded 

 sects; namely, those which have out of sight, 

 biting mandibles. In the second division, containing 

 the insects with sucking mouths, and without biting jaws, 

 the whole structure of the mouth appears widely different. 

 The stinging proboscis of the gnat, the fleshy blunt trunk 

 of the housefly, the long slender tongue of the butterfly, 

 all these display variation of structure. 



The " tongue" in these insects is composed of some or 

 other of the parts already mentioned, recognisable 

 though greatly altered from the biting type, and occasio- 

 nally so soldered together, or transformed in figure, that 

 nothing but a careful analysis can reduce them to a uni- 

 form plan. This will not be attempted here, but it would 

 be well for the reader to aim at tracing the connexion 

 existing in the organs of the various insects he dissects 

 from time to time. 



In the butterflies and moths a long tubular proboscis 

 is found, which coils up under the mouth when at rest 



D 



