SENSES OF INSECTS. 257 



are better calculated to assist an insect in threading the 

 dark and tortuous labyrinths through which it has often 

 to grope its way, and where antennae cannot be employed. 

 I have noticed that Hydrophili in which genus the 

 palpi are longer than the antennae when they swim, 

 have their antennae folded ; while the former are stretch- 

 ed out in front, as exploring before them. As these 

 are attached to the under-jaws and under-lip, we may 

 suppose they are particularly useful to insects in taking 

 their food; and upon this occasion I have often observed 

 that they are remarkably active. I have seen Byturus 

 tomentosus, a beetle which feeds upon pollen, employ 

 them in opening anthers ; and the maxillary pair appear 

 to me to assist the maxillae in holding the food, while 

 the mandibles are at work upon it. 



The arms or fore-legs of some insects are also organs 

 of active touch, being used, as we have seen, for cleaning 

 the head, digging, repairing their dwellings, and the 

 like 1 . By the Ephemerte, which have very short an- 

 tennae, the fore-legs, when they fly, are extended before 

 the head, parallel with each other and quite united pro- 

 bably to assist in cutting the air. The Trichoptera use 

 their antennae for the same purpose. 



Another sense of which the organ seems uncertain is 

 that of smelling, and various and conflicting opinions 

 have been circulated concerning it. Christian thought 

 that insects smell distant objects with their antennae^ and 

 near ones with their palpi b . Comparetti has a most sin- 



a VOL. II. p. 361. III. p. 544. * Lehmann De Sens. 



Extern, fyc. De Olfactu. 



VOL. IV. S 



