270 CLASS VIII. 
beetles, but especially in several Hemiptera, as well in the form of 
the accessory glands, as in that of the ¢estes and ovaréa, 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}. 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 Wie case, and supported by 
two horny threads?. 
Amongst the malformations of Insects hermaphroditic individuals 
occasionally occur, in which one half of the body is male, the other 
female, like the Androgyne in Africa, of whom the ancients fabled, 
and who had a female breast on the left side, and a male on the 
right®, This lateral bisexuality is most frequently seen in Butter- 
flies, in which it strikes the eye more readily from the form of the 
antenne or the colour of the wings‘; yet some instances of it are 
known in other orders also®. 
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 Chilognatha (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 vulvw, two penes), as in the crustacea. 
2 See the figures of Srraus (op. cit.) in the Cockchafer, Pl. 11. figs. 21, 22, Pl. v1. 
fig. 1. 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. 
HEcGETSCHWEILER, Diss. de Insectorwm genitalibus; cum Tab. Turici, 1820, 4to. and 
Geslechtsorgane der Insecten von DR Suckow in HeusinceEr’s Zeitschr. f. organ. Physik. 
11. Eisenach, 1828, s. 231—264, and further, F. Srern, Die weibliche Geschlechtsorgane 
der Kafer, Mit 1x. Kupfertaf, Berlin, 1847, 4to. 
3 C. Piini, Hist. nat. Lib. vii. cap. 2. 
4 For instance, in Bombyx dispar by SCHAEFFER, in Bomb. crategi, by ESPER 
(Beobachtungen an einer neu entdeckten Zwitterphalene, Erlangen, 1778, 4to.) in Vanessa 
wrtice, by Rapp (OKEn’s Isis, 1833, s. 235), &e. 
® As in Scolia maculata, by Romanp, Ann. des Sc. entomol. Iv. 1835, p- 191, in 
Lucanus cervus, figured in AsMuss, Monstruositates Coleopteror, Riga, 1835, Tab. X. 
