270 CLASS VIII. 



beetles, but especially in several Hemtptera, as well in the form of 

 the accessory glands, as in that of the testes and ovaria, in the num- 

 ber of the oviducts in the last and of the spermatic ducts in the 

 former, &c. We cannot however admit that this similarity has 

 the value of a general rule; the Lepidoptera, for instance, not to 

 speak of other Insects, exhibit an entirely different type in the two 

 sexes. 



The external sexual organs lie, as in the females, at the hind- 

 most part of the abdomen 1 . The penis has a very different form 

 and substance. Ordinarily it is surrounded by two horny plates, 

 and enclosed in a membraneous sac in the retracted condition ; in the 

 Coleoptera the penis is covered by a homy case, and supported by 

 two horny threads 2 . 



Amongst the malformations of Insects hermaphroditic individuals 

 occasionally occur, in which one half of the body is male, the other 

 female, like the Androgynce in Africa, of whom the ancients fabled, 

 and who had a female breast on the left side, and a male on the 

 right 3 . This lateral bisexuality is most frequently seen in Butter- 

 flies, in which it strikes the eye more readily from the form of the 

 antennae or the colour of the wings 4 ; yet some instances of it are 

 known in other orders also 5 . 



Before we turn from the consideration of the sexual organs of 

 Insects we must shortly notice another peculiarity observed in bees 

 and other Hymenoptera living in societies. Amongst these many 



1 The Chilognaiha (Julus) are an exception to this ; the parts, in both sexes, are 

 here situated very far forward, at a short distance from the head. They are also 

 double (two vulvce, two penes), as in the Crustacea. 



2 See the figures of STRAUS (op. cit.) in the Cockchafer, PL II. figs. 11, 22, PI. VI. 

 fig. I. WAGNER compares these horny threads with the ossiculum penis, found in 

 many mammals. On the sexual organs of insects, in addition to the works cited above, 

 two monographs (both, however, of somewhat old date) may be consulted, viz. J. J. 

 HEGETSCHWEILER, Diss. de Insectorum genitalibus; cum Tab. Turici, 1820, 4to. and 

 Geslechtsorgane der Insecten von DR SUCKOW in HEUSINGER'S Zeitschr. f. organ. Physik. 

 II. Eisenach, 1828, s. 231 264, and further, F. STEIN, Die weibliche Geschlecktsorgant 

 der Kdfer, Mit IX. Kupfertaf, Berlin, 1847, 4 to. 



3 C. PLINII, Hist. not. Lib. vn. cap. 2. 



4 For instance, in Bombyx dispar by SCHAEFFER, in Bomb, cratcegi, by ESPEB 

 (Beolachtungen an einer neu entdeckten Zwitterphalcene, Erlangen, 1778,4^.) in Vanessa 

 urticce, by RAPP (OKEN'S Isis, 1833, s. 235), &c. 



5 As in Scolia macnlata, by ROMAND, Ann. des Sc. entomol. IV. 1835, p. 191, in 

 Lucanut cervus, figured in ASMUSS, Mvnslrwsitates Coleopteror, Riga, 1835, Tab. x. 



