250 CLASS Vlll. 



antennulce), jointed threads, attached to the under lip (palpi labiales, 

 s. poster 'tores), and to the under jaw (palpi maxillares). The upper 

 jaws in Insects are not provided with palps. 



In masticating Insects, as Beetles, Locusts, &c., the parts of the 

 mouth, that have been described, may be best and most readily- 

 observed. In those which feed by sucking fluids the structure is in 

 appearance very different; yet even here it may be observed that 

 nature remains true to her plan, and that she has provided the 

 suckers not with different but with modified oral parts. We are 

 indebted to the illustrious SAVIGNY for the knowledge of that plan 1 . 



The sucking Insects possess oral organs which are named Tongue, 

 Beak, Sucker and Snout. 



The Butterflies ( Glossata FABR.) afford an example of what has 

 been called tongue, or spiral tongue (lingua, lingua spiralis). It is 

 a canal, occasionally of great length, composed of two laminoe which 

 are corneous or membraneous, on the inside excavated and round 

 externally. When at rest it is rolled up and concealed between two 

 palps. This was almost the entire amount of what was known of 

 the oral parts of Butterflies. But SAVIGNY pointed out in addition 

 two minute upper jaws, placed at some distance from each other, and 

 little, if at all, adapted for motion or mastication. The upper lip is 

 small and membraneous. The laminae of the tongue, as LATREILLE 2 

 had already shewn, are in fact nothing else than greatly elongated 

 and extended lower jaws. Their base is united to the head and upper 

 lip, and bears a palp composed of two or three joints. The two larger 

 palps which include the tongue and conceal it when at rest are 

 seated upon a triangular horny under lip. 



The case is similar with the suctorial apparatus of the Hemiptera, 

 (Bugs, Gicadce, &c.) named beak (rostrum). It consists of a horny 

 sheath (vagina) in which setas are contained (setce rostelli), that at 

 first sight appear to be three in number. The two lateral setae are 

 elongated upper jaws: the hair in the middle is double, and consists 

 of two similarly elongated and united under jaws: the under lip, 

 usually jointed, forms the sheath. In the same way in Diptera 

 (Flies, &c.) the under lip forms the snout (proboscis) . In its interior 



1 J. C. SAVIGNY, Memoires sur les Animaux sans vertebres, Paris, 1816, 8vo. lifere 

 fascicule. 



2 LATREILLE, Histoire naturelle des Crustacees et des Insectes. An. xn. 8vo. T. n. 

 p. 140. 



