STATES OF INSECTS. (Larva.) 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 (Pari). In the orders Diptera and Hymeno- 
ptera are many larve in which these organs have not 
been certainly discovered; yet Reaumur in that of a 
common fly (Mesembrina meridiana) found four retrac- 
tile nipples* which seem analogous to them; and La- 
treille has observed, that below the mandibles of those 
of ants are four minute points, two on each side>: but 
in all other larvee their existence is more clearly ascer- 
tained. The mazillary palpi vary in number, many 
having ¢wo on each maxilla and others only one. In the 
perfect insect the former is one of the distinguishing cha- 
racters of the predaceous beetles (Hntumophagi Latr.), 
but in the larvee it is more widely extended; since even 
in the caterpillars of Lepzdoptera the inner lobe of the 
maxilla which represents 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®; and it belongs to many other Coleoptera 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 re- 
gard to the form of the palpi, those of the Lepidoptera 
are mostly conical; in other orders they are sometimes 
setaceous and sometimes 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 maxillary. The latter never exceed four 
* Reaum. iv. 376. > N, Dict. d’ Hist. Nat. xii. 64, 
© Anat. Comp. iii, 322. 
VOL. III. K 
