INSECTS. 



4. In the Lepidoptera. — There are two diffL-rcnt forms in 

 this order : the bombyx pavonia will ferve as nii ex?.mple 

 of one, and die fame has been iniperfeflly exhibited by 

 Swammerdam and Malpighi in the filku'orm moth ( bombyx 

 niori). The common fpermatic canal is dinded into two 

 veficulae feminales, at firft a little enlaro;ed, and then pro- 

 longed in the form of tubes. They continue united to 

 each other in half their length. The vafa deferentia enter 

 in a very flender form into the fwellings of the veficulse. 

 They gradually enlarge, and terminate on each fide in a 

 mafs, wliich may be regarded as a tefticle. Malpighi has 

 reprefented the veficlcs broken a little above the infertion of 

 the vafa deferentia ; and Swammerdam a !it:Ie beyond this 

 point. The tefticles are fmallcr in the pavonia than in the 

 bombyx mori. 



The fecond form may be exemplified in the fphinx eu- 

 phorbia, and it is juft the fame as Swammerdam reprefents 

 in the papilio urtica;. The common canal, much longer, 

 is divided into two long and flender veficulne, each of which 

 is joined by a vas deferens : but the two lait, inftead of 

 Laving feparate teilicles, are united into a fingle rounded 

 mafs 



The preceding are the fpecies of infefts, in which Cuvier 

 has hitherto obferved the male organs : there are three 

 others in Swammerdam, which agree with tlicfe in the prin- 

 cipal points. 



The bee, among the hymenoptera, has two large oval ve- 

 ficulx, two rounded teiUcles, with long filiform vafa de- 

 ferentia. There are two ihort and fmall acccfTcry veficuix : 

 the common canal is enlarged before it enters the penis. 



In the order diptera the ilratyomys has two oval tefticle-^, 

 formed, like thofe of the filpha and gryllus, of fmal] vcfTels ; 

 two vafa deferentia, and two fimple filiform reficulic. The 

 common canal is of a middling fize. In the fly, which lays 

 in cheefe, on the contrary, there is a very long common 

 canal, very fhort vafa deferentia, and large oval veficulx di- 

 vided into two lobes. 



II. Female Organs. — Thefe are much more uniform than 

 the male in the whole clafs. They confiil, in general, of a 

 common oviduft, opening at the vulva, and divided at its 

 origin into two branches, each of which is again divided 

 into a certain number of conical tubes of various length. 

 The ova are fo arranged in the interior of thefe tubes, that 

 the largeft are the reared to the ovidud, and that the others 

 gradually decreafe in fize to the point of the tube, where 

 they are imperceptible. When the ova have been difchargcd, 

 the tubes remain empty. They may be already difcerned 

 in the chryfalis, a little before the metamorpholls. Secretory 

 veffels of various forms end in the oviduct, and depofit in 

 it fiuids for covering the eggs or for forming a (hell. 



The fcarabaeus naficornis has fix oviferous tubes on each 

 fide, each containing five or fix eggs : an oval veficle and 

 a fmall but rather long vclTel end in the oviduft. 



The carabi have ten or twelve tubes, snd the dytifci 

 twe!ve or fifteen ; the oviducl has a fimple and fmall bladder, 

 which-is prolonged further in the carabus. 



In the filplia atrata there are feven or eight tubes, and 

 each contains four eggs. The latter do not become large 

 until they arrive in the branches of the oviduct, which are 

 cf confiderabie fize. 



The tubes are very numerous in the hydrophilus, and 

 form two large branches ; round the bafis of each of thefe 

 artf five long and large fecretory veffels containing a green 

 liquor. ; 



The butterflies have on each fide four very long tubes, 

 filled with a larjje numlier of eggs, and forming, particularly 

 Ki the fruitful fpecies, rows like firings of beads, four cr 



five times longer than the body. The common ovidu.!! is 

 fo fhort as to be fcarccly perceptible j it receives one or tw* 

 veficles, and two long vcflels. 



Tlie grylli have on each fide about thirty tubes, each 

 of which does not contain more than three or four vifible 

 eggs : they are united by the trachcve, and by a mucous 

 fubllance, into two oval maiTes. The common oviduct re- 

 ceives a veficle and a long veffel. 



The bees have the two laft. mentioned parts : their rows 

 of eggs are numerous on each fide. Cuvier thinks that 

 he can perceive very fmall ones in the neuter bees, wliich 

 would confirm the notion of their being imperfectly deve- 

 loped females. 



In the filpha there are five, and in thenotoneda fix row* 

 on each fide. 



'! he libelhila have two very long branches ; their tubes 

 are fiiort, fmall, and ahnoll iiinuir.erable. 



The various boring inllruments which certain genera, 

 as the gryllus, ichijcumon, tenthredo, and cynip?, employ 

 for depofiting their ova in fuitable fituations, may be ar- 

 ranged v.'ith llic organs of the female fex. But, as thefe 

 parts are completely external, and have been well dtrlcribed 

 by naturalifts, we ihall not fay any thing more on the fuL- 

 jecl. 



Spinnhg FnilrumeiU of the Caterpillars. — Almoft all tlie 

 caterpillars ipin themielves a covering, or at lead an attach- 

 ment of fijine kind, before their metamorphofis. The ca- 

 terpillar' of the bombyx mori is the mod celebrated in this 

 refpect, fiiice the thread compofing its covering being abun- 

 dant, flexible, brilliant, and eafily wound ofi", forms the ma- 

 terial from which our mod fplendid filks are formed. Other 

 caterpillars, as that of the bombyx pavonia, f.jrin as large 

 a qfiantity of filk, but it is hard, liable to break, and can- 

 not be wound off. 



The fecretory organs producing the filk are the fame in 

 all caterpillar.";, excepting varieties in fize, which is pro- 

 portionate to the quantity of filk produced. Thefe, lilte 

 all the other fecreting organs of infedts, are two long tubes, 

 commencing in a very flender and convoluted form ; then 

 growing larger to form a kind of refervoir, and terminating 

 in an excretory canal fo fmall that it can hardly be feen. 

 The two canals terminate under the hiwer lip : and the 

 animal draws out and elongates the duiTtile matter by moving 

 its head from fide to fide. 



Organs for producing Light — Several animals cf this cLifs 

 have the pov.'er of producing light ; and the fubftance in 

 which this property refid-s is fometimes difTufed through 

 the animal's body, fonletimes collected into a particular 

 organ. The luminous matter mud be regarded as an animal 

 fecrction produced like any other animal iubllance. A very 

 full and intercding account of this fubjedt is contained in 

 a paper by Mr. Macartney, in the Philofophical Tranf- 

 a£tions for 1810, from which the following paflfages are ex- 

 tiafted. 



" The power of emitting light has been obferved in two 

 animals of the cru'.laceous order, and feemed to refide in 

 the whole body. One of thefe, obferved by fir .Jofeph 

 Banks, in tlie pafliige from Madeira to Rio Janeiro, re- 

 fembled the common fiirimp, but was lefs : it is namt d 

 by Mr. Macartney cancer fulgeiis. The other was found 

 in the Red fea by captain Horlburg, appeared to l>e a 

 monoculus, and to belo:;g to the genus limiihis of Miiiler. 

 Mr. Macartney calls it limulus noftilucus. A third crulla- 

 CC0U3 animal of the genus lynceus of Miiiler, poflefling 

 luminous properties, has heen feen off the coaft of Malabar. 

 Of other infects fome fpecies yield light in tlie five following 

 genera ; vis;, elatcr, lampyris, fulgora, paufus, fcolopen- 



dru. 



