EXTERNAL ANATOMY OF INSECTS. 451 



tions as to figure, of which this joint exhibits examples. 

 The palpi in general at their vertex are often rather con- 

 cave ; and this concavity is formed by a thin papillose 

 membrane, which it is supposed the animal has the 

 power of pushing out a little, so as to apply it to sur- 

 faces. The "primary use of the palpi of insects will be 

 considered when I treat of their senses; but they proba- 

 bly answer more purposes than one. For instance, when 

 I was once examining, under a lens, the proceedings of 

 a species of Mordella, which was busily employed in the 

 blossom of some umbelliferous plant, it appeared to me 

 to open the anthers with its maxillary palpi, and they 

 often held the anther between them : when not so em- 

 ployed, they were kept in intense vibration, more than 

 even its antennas ; and at the same time, as far as I could 

 judge, an Elater made the same use of them. 



7. Lingua a . — This name was applied by Linne to the 

 part in insects representing the tongue in vertebrate ani- 

 mals ; and as it performs most of the common offices of 

 a tongue, and the pharynx is situated with respect to it, 

 as we shall presently see, nearly as it is in those ani- 

 mals, there seems no more reason for giving it a new 

 name, than there is for giving a new name to the head 

 or legs of insects, because in some respects they differ 

 from those of the higher animals. I shall not therefore 

 call it Ligula, with Fabricius and Latreille, nor Labium, 

 with Cuvier and others, but adhere to the original term, 

 which every one understands. 



The tongue lies between the two lips — the lahrum and 

 labium. On its upper side, at the base, it meets the pa- 



■ Plate VI. VII. XXVI. e'. 



2 G 2 



