250 CLASS VIII. 
antennule), jointed threads, attached to the under lip (palpi labiales, 
8. postertores), and to the under jaw (palpi mawillares). The upper 
jaws in Insects are not provided with palps. 
In masticating Insects, as Beetles, Locusts, &e., 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 SAvieNy for the knowledge of that plan!. 
The sucking Insects possess oral organs which are named Tongue, 
Beak, Sucker and Snout. 
The Butterflies (Glossata F apr.) 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 laminee 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 SaAviany 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 lamine of the tongue, as LATREILLE? 
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, Cicadw, &c.) named beak (rostrum). It consists of a horny 
sheath (vagina) in which sete are contained (sete rostelli), that at 
first sight appear to be three in number. The two lateral sete 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, &e.) the under lip forms the snout (proboscis). In its interior 
1 J.C. Savieny, Mémoires sur les Animaux sans vertébres, Paris, 1816, 8vo. Jitre 
fascicule. 
2 LATREILLE, Histoire naturelle des Orustacées et des Insectes, An, xt. 8vo. T. I. 
p- 140. 
