400 



Div. 3. ARTICTJLATA.— INTRODUCTIOX 



minute [hexagonal] lenses or facets, to each of which there is a corresponding filament 

 of the optic nerve. These two kinds of eyes may exist in conjunction or separately, vary- 

 ing in the genera ; and we know not whether their action, when united in the same 

 individual, be essentially different. The sense of sight, however, must in all instances be 

 effected in a manner quite unlike that of the Vertebrata. (Consult the Memoir of 

 Serres on the Eyes of Insects, Montpelier, 1815, 1 vol. 8vo ; and the Observations of 

 Blainville on the Eyes of Crustacea, in Bull. Soc. Philomat.) [also the memoir of 

 J. Midler, conscisely abstracted in the " Insect Miscellanies."] 



Other organs, which we here find, for the first time, amongst the Crustacea and 

 Insecta*, and which are named antennae, are articulated filaments, varied in the greatest 

 degree as to their form, even in the sexes of the same species, arising from the head, 

 and appearing eminently endued with a delicate sense of touch, and perhaps, also, with 

 some other kind of sensation of which we have no idea, but which has reference to the 

 state of the atmosphere. 



These animals also enjoy the senses of smell and hearing. Some authors place 

 the seat of the first of these senses in the antennae f ; others, as M. Dumeril, in the 

 orifices of the breathing pores ; and others, as M. de Serres, in the palpi. These 

 opinions, however, are not founded upon positive and conclusive facts. As to the sense 

 of hearing, the Decapod Crustacea, and certain Orthoptera, alone possess a visible ear. 



The mouth of these animals presents a great analogy [or general uniformity], which 

 also extends, according to SavignyJ, in a relative manner, even to those species which 

 subsist by suction. Those which gnaw their footl [^landibulata, Clairville] by means 

 of jaws fit for trituration, have the parts of the mouth arranged in pairs laterally, and 

 placed one before [or over] the other. The anterior pair are specially named mandibles, 

 [the succeeding pair or pairs being termed maxillae, or hind jaws] ; the pieces which 

 cover the jaws before and behind are the lips§, that in f'-ont being called the labrum, 

 [and that behind being the labium]. The palpi are articulated filaments attached to 

 the hind jaws and the hind or lower lip, and appear to assist the animal in 

 recognizing its food. The form of these different organs determine [or, more properly 

 speaking, indicate] the kind of nourishment with as much precision as the dental 

 system of Mammalia. Within the lower lip||, the tongue (ligula) [or rather lingua] 

 is ordinarily attached. Sometimes, as in the bees, and many other Hymenoptera, it is 

 prolonged considerably, as well as the maxillae, forming a kind of proboscis (promuscis), 

 with the pharynx at its base often covered by a kind of secondary lip {sous-Iahre ; 

 epipharynx, Savigny), and which appears to me to exist, in many beetles, in the form 



• And even in the AracbiiHn, bnl under ntodi^ed forms, and with 

 BiudiBcd ftiiictinnft. 



+ With reference, iit Icmt, to Insect*, und when thej terminste in 

 % more or le»» complicnted mnss, or are clothed with a creat quantity 

 of hairs. AccnrUinK to M. Desvoidjr, the inlernal nnli-nna of the 

 Decapo<l Croslarr* are nr|;anii of smell (Hull. Sri. A'«/. ItT), hot he 

 cites no tlireet proof; niid, indeeil, in the must carnivorous cralis 

 (Grc/irrinuj, &c), where the orpin of smell iini;ht to he most folly 

 developed, the very reverse takes place, [the inner antennK beinif 

 very small.] 



X M^moirrs siiT les .i^nimnnr ttms f'rrOhrrt. Tlie orif^inal idea [of 

 this uniforinitv] was first announced by me (but without develope- 

 ment) in my Histoirr G^nfralr ttrs Insrctra^ 



^ I here more pHrticularly allude to the flpxnpod inserts. 



i The labium is protected in front by a corneous piece, formed by a 

 cutaneous elongation, and articulated at its ba^e with a part of the 

 uniler side of the head, named the mentom. Its two palpi are termed 

 labial piilpi. The maxillary pnlpi arc two or four in number, in the lat- 

 ter case being named external and internal, the internal palpi beinff a 

 modification of the outer lobe of the maxillx, and which is named 



galea by Fabricios, in Ortho^rterous insects. In these insects, and in 

 the LibelUilse, there is a soft vesiculose body in the middle of the 

 nwjuth, distinct from the lower lip, and which, compared with the 

 Crustacea, appears to be the true tnsicue (L'iirism, Fabr.) This 

 vr^an is probably represented m nmny CoU'optera by the lateral divi 

 sions of tile l.ilnum, which are termed paiajjlossa. The membranoi'S 

 terminal part of the lower lip, extendiii|t between the palpi in the 

 Orthoptera and l.ibi llular, is qoite distinct from this central tonjjuc, 

 althoui,'li nearly all entomologists have termed this terminal extremity 

 of tilt lip \*y the name of tani^uette. It is, nevertheless, true, that this 

 central tongue is often closely soldered to the [inner surface of] the 

 lower lip. [The comi»osition of the lower lip is very complicated, 

 and v.ariable in different groups. As a whole, it is best to retain for it 

 the name of labium. Its corneous basal piece is the mentum. The 

 f>dlowing piece is generally called the labium, having the Labial palpk 

 arising at its base; but the German authors term this terminal piece 

 ligula. The inlemal piece is the lingua, l.atrcille refers to the 

 larvie of the I>yticidap, as alTording a clear notion of the typical struc 

 lure of the labium; but in these lar^•ac, the labium is almost obsolete. 

 The perfect Silphte, or Slaphyliui, afford much better instances.] 



