$ 351. THE INSECTA. 457 
§ 351. 
The External Genital Organs ofthe females are pretty simple with the Ap- 
tera, Hemiptera, Lepidoptera, Coleoptera, with many of the Diptera, Orthop- 
tera, and Neuroptera, and with some Hymenoptera. The orifice of the vagina 
is supported by an upper, and two lateral horny plates, whose size and form 
vary according to the species. With only some Coleoptera, Diptera, and 
Hymenoptera, the end of the vagina is protractile, appearing as a more or 
less articulated Vagina tubiformis.” These horny plates about the 
vaginal orifice serve to support the penis during copulation, and to facilitate 
the escape of the eggs during oviposition.” With the Acrididae, these 
plates are conical, and in two pairs, one upper, and one under, which 
may be opened and shut in a pincer-like manner. With several genera of 
the Tipulidae, and Asilidae, the two lateral plates are very long, and form 
a simple ovipositor (Vagina bivalvis).© With Boreus, and Acheta, this 
ovipositor is long, and with Raphidia, it is long and acinaciform. The 
Locustidae have also a similar and very prominent ovipositous sabre, but 
more complicated in that each of its plates is divided into three pieces, 
which are so disposed that the two internal, soft, are surrounded in a sheath- 
like manner by the four others, which are horny. With the Tenthredini- 
dae, and with Aeschna, Agrion, and Calopteryz, there is an analogous, 
apparatus situated at the posterior extremity of the abdomen, and covered 
by two valves, only that its pieces are denticulated in a saw-like manner, 
and therefore is called saw-ovipositor.” With the Siricidae, the ovi- 
positing apparatus is likewise composed of two horny, denticulate plates ; 
but is more auger-like in its form, and, with some species, projects far 
beyond the short lateral valves. 
The Ichneumonidae, Cynipidae, and Cicadidae have a more or less long 
ovipositor (Terebra), composed of two lateral groove-like sheaths, between 
which plays a kind of sting composed of two intimately-united horny 
shafts. This sting serves, partly to pierce the substance in which the eggs 
are to be deposited, and partly to push the eggs along the sheath formed 
by the groove-like valves. All these different ovipositors have a muscu- 
lar apparatus at their base, by which their component pieces are moved. 
With some Libellulidae, there is a peculiar groove-like appendage on the 
penultimate abdominal segment. 
1 The ovipositor is unarticulated and protractile 
with the Cerambycidae, while it is articulated with 
the Chrysididae aud many of the Muscidae. In this 
last case, its pieces are movable, like the tubes of a 
telescope. They are only the terminal abdominal 
segments modified; see Z. Dufour, Ann. d. Sc. 
Nat. I. 1844, p. 383, Pl. XVI. fig. 16 (Piophila). 
2 For the oviporitor of Insecta, see Burmeister, 
Handb. &c. I. p. 209, Taf. XIL., and Lacordaire, 
Introduct, &c. IT. p. 353. 
3 Limnobia, Ptychoptera, Tipula, Ctenopho- 
ra, Asilus, [aphria. Among these Diptera, 
Ctenophora rufcornis is particularly distinguished 
by the length oy the horny plates composing the 
ovipositor. 
4 For the str ‘cture of this saw-like ovipositor, 
see Lyonet, M¢-1. du Mus. XIX. p. 57, Pl. VI- 
VIII. (14-16) () uches a scie) ; and Hartig, Die 
Adlerflugler De. achl. p. 37, Taf. I. u. d. f. 5 also, 
Réaumur, Mév VI. 11 mémoire, Pl. XL. fig. 6- 
39 
It serves to receive the egus at the 
9 (A4grion). It is well known that these Insecta 
use this ovipositor to pierce the epidermis of 
plants, and to introduce therein their eggs. The 
deposition of the eggs with the Tenthredinidae 
has been described with details by Dahivom (Isis, 
1837, p. 76) and by Ratzeburg (Forstinsekten, 
Th. III. p. 65). I have, also, observed this act with 
eerie: Sorcipula (Wiegmann’s Arch. 1841, I. p. 
5 Hartig and Ratzeburg have given a detailed 
description of the auger of the Siricidae ; it is par- 
ticularly long with Xiphydria and Sirexr. 
6 For the ovipositor of the Hymenoptera, see 
Hartig, Die Adlerfliiger Deutschl. p. 163 in 
Wiegmann’s Archiv, 1837, I. p. 151, and in 
Germar’s Zeitsch. IIJ. p. 326; Ratzeburg, Me- 
diz. Zool. II. p. 145, Taf. XXIIL. (Cynips). Fur 
that of the Cicadidae, see Réaumur, Mem. V. 
4 mémoire, Pl. XVIII. ; and Doyere, Ann. d. Se 
Nat. VII. 1837, p. 193. 
