STATES OF INSECTS. 129 



As these animals are found in almost every ditch, you 

 will doubtless lose no time in examining for yourself an 

 instance of so singular a construction. 



Feelers (Palpi). In the orders Diptera and Hymeno- 

 ptera are many larvae in which these organs have not 

 been certainly discovered; yet Reaumur in that of a com- 

 mon fly [M. meridiana L.) found four retractile nipples a 

 which seem analogous to them; and Latreille has ob- 

 served, that below the mandibles of those of ants are 

 four minute points, two on each side b : but in all other 

 larvae their existence is more clearly ascertained. The 

 maxillary palpi vary in number, many having two on 

 each maxilla and others only one. In the perfect insect 

 the former is one of the distinguishing characters of the 

 predaceous beetles (Entomophagi Latr.), but in the larvae 

 it is more widely extended; since even in the caterpillars 

 of Lepidoptera the inner lobe of the maxilla which re- 

 presents this feeler is jointed, which is precisely the case 

 with the beetles just named. Cuvier has observed this 

 circumstance in the larva of the stag-beetle c ; and it be- 

 longs to many other Coleopiera that have only a pair of 

 maxillary palpi in the perfect state. The labial palpi are 

 always two, emerging usually one on each side from the 

 apex of the under-lip. With regard to the form of the 

 palpi, those of the Lepidoptera are mostly conical ; in 

 other orders they are sometimes setaceous and some- 

 times filiform. Their termination is generally simple, 

 but sometimes the last joint is divided. They are for the 

 most part very short, and the labial shorter than the 



a Reaum. iv. 376. b N. Diet. d'Hist. Nat. xii. 64. 



c Anat. Comp. iii. 322. 

 VOL. III. K 



