EXTERNAL ANATOMY OF INSECTS. 19 



their peculiarities. To describe a single order would be merely 

 to mislead ; to describe all would be extending my letter to an 

 unreasonable length. 



The LABIUM or lower lip corresponds with the upper lip. 

 It occupies the same situation below the jaws that the upper 

 lip holds above them. The upper and lower lips therefore close 

 the mouth vertically. There is no part of the mouth con- 

 cerning which writers are so little agreed as this. The difficulty 

 has arisen in two ways ; — first, from the number of its parts ; 

 secondly, from the propinquity of similar parts. The lower 

 lip is a compound and somewhat complicated organ. Every 

 one has seen this ; and every one has been desirous of applying 

 some name to each of its parts. The next organ above it is 

 the tongue ; the next part below it is the menttim. It is not 

 much to be wondered at that entomologists finding these three 

 names— finding three very distinct parts in the lip — and 

 moreover, very frequently finding no distinct tongue or mentum, 

 should have applied the three names, tongue, lip, and mentum 

 to the three most conspicuous and manifest divisions of the lip. 

 The name mentum was given by Reaumur. Now the names of 

 Reaumur impose no law : did they, half our present nomencla- 

 ture must be abandoned. Latreille has, however, decided on 

 retaining the name, and has applied it to the part of the throat 

 immediately adjoining the mouth. The lower lip is divisible 

 into four portions : — the Insertio or insertion ; the Labium of 

 Fabricius, or true lip ; the Palpiger or feeler-hearer ; and the 

 Ligula of Fabricius, or limb. Of these, the palpiger appears 

 to be now noticed for the first time. The insertion is precisely 

 what the name implies ; it is, in fact, the root by which the lip 

 holds. It is always, in a greater or less degree, concealed 

 by the mentum. Savigny has called it support and inser- 

 tion. MacLeay, it will be seen, has named it stipes; — a name 

 not inapplicable to the particular instances in which he figures 

 it. The true labium is the second part : it is thus named bv 

 Fabricius, and has since been erroneously termed the mentum 

 by most modern entomologists. The palpiger, or feeler-bearer, 

 is situated above the disk, and is very often confounded with it. 

 It seems generally to be a mere fleshy fold, between the lip and 

 the ligula, but is occasionally thrust out far beyond the lip, 

 and assumes the appearance of a ligula. In these instances it 

 is easily detected by the feelers which it bears on its summit. 



