CRUSTACEA, ARACIINIDES, INSECTA. 
149 
for instance, in the orifices of tlie tracheae, and Marcel de Serres, &c. 
in the palpi ; neither of these opinions, however, are corroborated by 
positive and conclusive facts. As to the second, it is only in the 
Crustacea Decapoda, and some few of the Orthoptera, that we can 
find a visible ear. 
The mouth of these animals presents a great analogy, which, 
according to Savigny* *, and at least Avitli respect to the Hexapoda, 
extends to those which can only feed by the suction of liquid 
aliment. 
Those called Tritores or Grinders (broyexirs), on account of their 
having jaws fitted for triturating their food, always present them in 
lateral j^airs, placed one before the other ; the anterior pair are 
especially called mandildes ; the pieces which cover them before and 
behind are named lahia-\, and the front one, in particular, labrum. 
The palpi are articulated filaments attached to the jaAvs or to the 
lower lip, and appear to be employed by the animal in recognizing 
its food. The form of these various organs determines the nature 
of the regimen with as much precision as the teeth of quadrupeds. 
The ligula, or tongue, commonly adheres to the lower lip;];. Some- 
times, in the Apes and other Hymenopterous insects, it is consider- 
organ, Bullet, des Sc. Nat. ; but he adduces no one direct experiment in proof of his 
opinion. It would, if tliis were so, seem probable that in the highly earnivo- 
rous Crustacea, such as the Gecarcini and others, we should find this organ in a com- 
paratively greater state of development, whereas the fact is directly the reverse. His 
ideas respecting the external composition of the Crustacea Decapoda suppose the 
existence of a skeleton. He should have commenced, however, by establishing the 
connexion of these animals with the Fishes, and not by admitting, as a positive fact, 
what is at least a matter of doubt. 
* Memoire sur les animaux sans vertebres. The original idea was throw'n out, but 
undeveloped, in my Hist. Gen. des Insectes. 
-f- We here more particularly alude to insects with six feet, or to the Hexapoda. 
X Or rather labium, since the other is termed labrum. It is protected, before, by 
a horny production formed by a cutaneous prolongation, and articulated at the base 
with an inferior portion of the head called the mentum or chin. Its palpi, always two 
in number, are distinguished from those of the maxillse by the epithet labial. When 
the latter amount to four they are designated as external and internal ; they are con- 
sidered as a modification of the external and terminal division of the maxillae. This 
production, which, in his Uloncates or the Orthoptera, Fabricius termed the Galea, is 
still the same maxillary division, but more dilated, arched, and fitted to cover the 
internal division which, here, on account of its scaly consistence and of its teeth, 
resembles a mandible. In the last insects, and particularly in the Libellulae, the 
interior of the buccal cavity presents a soft or vesicular body, distinct from the lip, 
and which, compared to the Crustacea, appears to be the true tongue — labium, Fab. 
This part is perhaps represented by those lateral divisions of the ligula termed para- 
glossae. (See the Coleoptera Carnivora, Hydrophili, Staphylini, the two pencil- 
shaped pieces that terminate the lip of the Lucani Apiarice, &c.) The above- 
mentioned Insects, the Orthoptera and the Libelluloe of Linmeus, evidently demon- 
strate that this membranous and terminal portion of the inferior lip, which projects 
more or less between its palpi, and is particularly elongated in several of the Hyme- 
noptera, is very distinct from that internal caruncle which I consider the tongue 
