PARTS OF INSrCTS. 29 



tentively examined at the base, will be frequently found of a horny sub- 

 stance. 



In the Cokopfera, and in some of the JJcmiptera Tas in Bhitta, Gn/Hus, 

 Si-c), this appendage terniuiates at the point in a nienibranaccous sub- 

 stance: — its form is extremely various in the difierent genera. The 

 Hi/mt)ioj)tcra and some Ni'tuopttra have the %m/u situated in the 

 same manner; but it is in these concave, and is frequently ])rolong- 

 ed into a sort of proboscis, which sometimes exceeds the lengtii of the 

 whole body. It is membranaceous, but of a soft and spongy texture, 

 and well suited for receiving the impressions of taste. Tiiis kind of 

 process is extremely well exempliticd in the bee. 



Lingua, the Tongue: an involuted tubular organ, which constitutes 

 the whole mouth in Icpidoptcrous ins"Scts. This is of a setaceous form, 

 and either very long, as in the FapUio and Sp/iiiix genera; or short, as 

 in most of the Bo/nbi/ccs and other moths. It consists of two filamen- 

 tous pieces, which are externally convex, concave within, and connected 

 longitudinally by a suture along the miudle above and beneath. These, 

 in uniting, form a cylinder, through which the ncctareous juices of tlie 

 flowers on which these insects subsist are drawn up with facility. 

 These two pieces are not very closely united, and may be separated by 

 means of a needle point. When the insect takes its food, this tube is. 

 exserted; at other times it is rolled up spirally between ihc palpi. 



liosTKUM, or Beak: the part which forms the mouth in muny of the 

 hemipterous order of insects. This instrument is moveable, articu- 

 lated, and bent imder the breast. Witliin, this beak is hollow, imd 

 contains, as in a slicath, three or more very fine and delicate bristles^ 

 the points of which these insects introduce into the body of the ani- 

 mal, or substance of the plants, from wliich they draw nourishment. 

 The rosti-um is conspicuous in the genera Cicada, Kcpa, and Ci/ne.v. 



Proboscis, the Trunk: inserted in the })lace of the mouth in most 

 dipterous insects. It is rather tieshy, retractile, of a single piece, and 

 often cylindrical ; the end forming t%vo lips, which are of a soft suIj- 

 stance, and from the delicacy of their teguments mu-st possess the fa- 

 culty of taste in a very high degree. Example in the House-fly. 



Lingua, 7-ost?-u)n, and proboscis, are Linnean terms ; and are adopted 

 according to the definition of thtit aullior. Ligula is a I abrician ex- 

 pression, indicating a process of the lower lip. 



Haustellum : formed of two or more very small and delicate fila- 

 ments, inclosed in a sheath of tvvo valves. 



Palpi, Feelers. These are the small, moveable, filiform organs or 

 appendages, placed at each side of the mouth in the generality of 'n\- 

 sects. In some respects they resemble the antenna-, but are more 

 distinctly articulated. They vary in number in different insects, being 

 either two, four, or six, (P/. 10. fig. i.f-f. and g.) and are commonly in- 

 serted at each side the exterior part of the jaw. In those which have 



