EXTERNAL ANATOMY OF INSECTS. 81 



orders of Coleoptera exhibit many variations in the parts of 

 this oi'gan, but mostly analogous to those described. 



In OrtJioptera, the lip has the same development as in Cole- 

 optera, but the ligula is much more produced. It is divided 

 into four lobes, somewhat palpiform. The common cock-roach 

 presents an instance of this. The feelers are four-jointed ; the 

 basal joint occasionally amalgamating with the feeler-bearer. 



In Hemiptera the lower lip wraps itself round the mandi- 

 bles, &c., forming a sheath for them. It is four - jointed. 

 Savigny considers the basal joint to be the true lip,* if I com- 

 prehend rightly his meaning. Latreille, in his last work, still 

 treats of the lower lip as a quadri-articulate sucker, assigning 

 no names to the articulations. I suppose the four joints to 

 be analogous to the insertion, labium, feeler - bearer, and 

 limb, observable in Hymenoptera, Coleoptera, and OrtJiop- 

 tera. Savigny has figured what he considers the feelers of 

 Hemiptera, on the part which I have called the feeler-bearer. 

 Willing as I must be to prove the correctness of this idea, I am 

 compelled in fairness to admit that I have never made them 

 out to my own satisfaction. The lower lip in Hemiptera 

 varies scarcely at all, except in length. In the Linnaean genus, 

 Aphis, several instances occur of its being twice as long as the 

 body, passing beneath it, and projecting beyond it, like a tail. 



In the larvae of the Libellulites the lower lip has a most 

 wonderful development, and all its parts are very conspicuous ; 

 the insertion is short, but distinct; the labium is long, stout, 

 and incrassated externally ; the feeler-bearer is still more deve- 

 loped, in JEschna, it is full half an inch in length, and divided 

 into two lobes ; the feelers are prehensile and mandibuliform ; 

 in fact, much resembling the mandibles of Cicindela; the 

 ligula is a thin plate spread over the interior surface of the 

 feeler-bearer, and filling up the space which occurs between 

 its lobes. The most remarkable character of this extraor- 

 dinary lip is its articulation. The labium is so freely articu- 

 lated to the insertion that it is capable of being bent under 

 the body of the insect reaching to the metacoxa. The articu- 

 lation of the feeler-bearer to the labium is of the same kind ; 

 while the latter is bent below the insect, the former is 

 directed forwards, and reaches to the front of the mouth ; 



« Elle (la l6vre inf^rieure) est composee de quatre articulations, dont la 

 premiere repr^sente la ganache des Coleopteres et des OrthoptSres. — Savigny. 

 NO. I. VOL. II, M 



