150 CRUSTACEA, ARACHN1DES, INSECTA. 



ably elongated, as are also the jaws, forming a sort of false proboscis 

 (promuscis) at the base of which is the pharynx, and frequently 

 covered by a sort of sub-labrum, styled by M. Savigny the cpipha- 

 rynx *. At other times, in the Hemiptera and Diptera, the mandibles 

 and maxilke are replaced by scaly pieces in the form of setae, which 

 are received in an elongated tubular sheath, that is either cylindrical 

 and articulated, or formed with more or less of an elbow, and termi- 

 nated by a kind of lips. In this case they constitute a true proboscis. 

 In others that also live by suction, the Lepidoptera, the maxilla 

 alone are greatly elongated and united, producing a tubular setiform 

 body, resembling a long, slender, and spiral tongue (or the spiri- 

 trompe, Lat.) ; the remaining parts of the mouth are considerably 

 reduced. Sometimes again, as in many of the Crustacea, the anterior 

 feet approach the maxillae, assume their form, and exercise part of 

 their functions the latter are then said to be multiplied. It may 

 even happen that the true maxillae become so much reduced, that 

 the maxillary feet supply their place in toto. Whatever bo the 

 modifications of these parts, however, they can always be recognized 

 and referred to a general type f . 



properly so called ; notwithstanding this, nearly all Entomologists designate this 

 external extremity of the lip by the name of ligula or lanyudte. To say, however, 

 that the tongue properly so called, is usually so intimately connected with the lip 

 that at the first glance they seem to be confounded, is correct. The pharynx is situ- 

 ated in the middle of the anterior face of this lip a little above its root, and in the 

 Coleoptera provided with paraglossse, at their point of union. In order to under- 

 stand well the primitive composition of the under lip, it must be studied in the larvae, 

 and chiefly in those of the Aquatic Carnivorous Coleoptera. See General Obser- 

 vations on Insects. 



* There is a membranous production beneath the labrum, in many Coleoptera, 

 which appears to me to be analogous to the epipharynx. The latruin is to it, what 

 the incutum is to the labium. 



f It is only by a comparative and gradual study of the mouth of the Crustacea, 

 that we can acquire correct and exact ideas respecting the various transformations 

 of these parts, and the means (f establishing, if not a certain, at least a probable 

 general concordance between these various organs in the three classes. The man- 

 dibles, maxillae, and the labium, are in fact, a sort of feet appropriated to the masti- 

 catory or buccal functions, but susceptible of being so modified as to become organs 

 of locomotion. This principle even extends to the antennae, or at least to the two 

 intermediate ones of the Crustacea. By adopting it, we are enabled to reduce the 

 composition of these organs to one general type, and we shall hereafter sec that, in 

 this respect, neither the Arachnides nor Myriapoda present any anomaly. 



