850 



INSECT. 



As to their size, antennae are exceedingly variable, 

 as they are also in their length, being some- 

 times shorter than the head, and at others several 

 times longer than the entire body ; in many instances 

 they are as slender as a hair, and at other times 

 nearly as thick as the body. As to their direction, 

 they are generally porrected in front of the head ; 

 others throw them over the back ; in some they are 

 stiff, in others flexible ; they are straight, deflexed, or 

 spiral, and are often, when at rest, lodged in par- 

 ticular cavities prepared for their reception on the 

 under side of the head or thorax. 



The number of joints of which these organs are 

 composed, merits a few observations. Coleopterous 

 insects have in general eleven joints ; the Heteroptera 

 from four to six ; the stinging Hymenoptera twelve in 

 the females and thirteen in the males ; but in the 

 Lep'uloptera, Iclmeumonidte, Orthoptera, and many 

 others, the number of the joints is much more con- 

 siderable, sometimes reaching fifty or sixty ; and in 

 some Orthoptera the number is much more numerous. 



In a few insects the antennas are very short and 

 destitute of joints, as in the Hippoboacidce, and in 

 Dulmann's genus Articerus; 21i-articjifate(tv;o-jo'mted) 

 antennae are found in Paussus, Inarticulate antennae 

 in many Dlptera. The large sawflies (Cimbiccs) 

 vary in the number of their joints from five to eight. 



It still remains to be noticed, that a very great 

 diversity often exists in the structure of the antenna; 

 in the opposite sexes of the same species ; this is 

 especially noticed in the greatly increased length of 

 these organs in the males, and in the various hairs, 

 feathers, or branches with which they are adorned 

 in this sex. Numerous other variations occur, such 

 as the incrassation of certain of the joints, or their 

 greater development, to enumerate which would 

 occupy too great a space ; but in all which these 

 advantages are always in favour of the male ssx. 



d. The Mouth*. (M in the figures). 



If the structure of the antennae has required a con- 

 siderable portion of our attention, a still greater share 

 must be now devoted to the various and varia- 

 ble organs of which the mouth of insects is composed 

 since it is upon these variations that the most valuable 

 arrangements of insects hitherto proposed have in a 

 great measure, been established. If a beetle and a but- 

 terfly a house-fly, or a bug, be examined whilst feeding- 

 a totally different apparatus will be found in each 

 although perfectly adapted for the mode of feeding 

 1 he beetle is employed in gnawing and teariiwr 

 in pieces hard or fleshy substances : its instru- 

 ments of manducaUon are therefore horny and robust 

 I he butterfly, on the contrary, has to suck its 

 food at the bottom of the tubes of flowers, and here 

 in the glowing beams of the sun it revels in its ex 

 istence, and sips the most delicious nectar It is 

 nece ssary f or this p that u should 



With a long and slender instrument; but, from the 



' 



i II *~mo> it is castJilliai 



e, that so soon as the insect has ceased fc 

 &e^ 



d to rest between a pair of hairy appendages 



i,,s*mtTh I e n s i b m e e^ r US in&p 8 1 ^ resenti "? the mouth of 

 / I, is the "PP^-r li,/, labrumtm mandfble m m ^^ throu K hout ; 



which will defend it from injury If we observe a 

 common fly sipping up a drop of spilt wine, or revel- 

 ling upon a morsel of sugar, it will be found that its 

 mouth is totally unlike either of the former, it is short, 

 thick, and fleshy, and acts as a sucker, the nutriment 

 ascending through the canal which runs upwards into 

 the throat. The disgusting bug, and all its brethren, 

 have a mouth still differently constructed, being a 

 long and slender-jointed canal of a fleshy or leathery 

 substance, but furnished internally with several slen- 

 der bristles, which the insect employs as lancets to 

 wound its prey. In the flea again the structure is 

 quite different. 



Fig. 87 Antlia of Lepidoptera (Sphinx). 



These insects may be cited as affording examples 

 of the chief variations which occur in the general 

 structure of the mouth, and to each of which, as a 

 variation of the mouth, a name has been applied. 

 Thus the mouth of the butterfly and other lepidop- 

 terous insects (fig. 87), is termed by Kirby and Spence 

 antlia ; by Fabricius lingua (an evidently exception- 

 able term, being only strictly applicable to a single 

 organ of the mouth) ; and by Latreille, spirignatha. 

 The mouth of the fly (fig. 88), is termed by Kirby and 



Proboscis of Diptera (Tabanus). 



Spence, Linnaeus, and Fabricius, proboscis. The mouth 

 of the bugs (fig. 89) is denominated by Kirby and 

 Spence, a pronmscus; but by Fabricius, Olivier, and 

 Latreille, rostrum, a term more properly applicable 

 to those insects which have the head produced in front 

 into a beak or snout, as the weevils or scorpion-tailed fly 

 (Panorpa), but which latter Latreille, for distinction, 

 terms proboscirostrum. The mouth of the flea is termed 

 a rostrulum, by Kirby and Spence ; and rostellum, by 

 Latreille, the latter name having been proposed by 

 Kirby and Spence for the suctorial organs of the 

 louse tribe (Pediculidai), but which Latreille terms 

 siphunculus. Moreover, the mouth of the bee, which 

 is chiefly organised upon the same plan as the biting 

 mouth of the beetle, but has its parts elongated so as 

 to lap up up the honey of flowers, is termed by La- 

 treille a Promuscus (although that term had been 

 given by Kirby and Spence to the mouth of the bug 

 tribes). 



Throughout this great variation of structure, how- 

 ever, the strictest uniformity is maintained, the same 



