§ 351. THE INSECTA. 457 



§ 351. 



The External Genital Organs of the 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 Calopteryx, 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 diiferent 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. It serves to receive the eggs at the 



1 The ovipositor is uuarticulated aud protractile 9 (Agrion). It is well known that these Insecta 

 with the Cerambycidae, while it is articulated with use this ovipositor to pierce the epidermis of 

 the Chrysididae and many of the JIuscidae. In this plants, and to introduce therein their eggs. The 

 last case, its pieces are movable, lilie the tubes of a deposition of tlie eggs with the Tentln-edinidae 

 telescope. They are only the terminal abdominal has been described with details by Dahlbom (Isis, 

 segments modified ; see L. Dufour, Ann. d. Sc. 1837, p. 70) and by Ratzeburi^ (Forstinseliten, 

 Nat. 1. 1844, p. 383, PI. XVI. fig. 16 {Piophila). Tli. III. p. 65). I have, also, observed this act with 



2 For the ovipositor of Insecta, see Burmeister, Aarioyiforcipula (JViegmann's Arch. 1841, I. p. 

 Handb. &c. I. p. 209, Taf. XII., and Lacordaire, 205). 



lutroduct. &c. II. p. 353. -5 Hartif^ and Ratzeburg have given a detailed 



■'! Limnobia, Pti/choptera, Tipula, Ctenopho- description of the auger of the Siricidae ; it is par- 



ra. Asi/uK, Laphria. Among these Diptera, ticularly long with Xiphydria and Sir ex. 



Ctenoplwra riijiconiis is particularly distinguished U For the ovipositor of the Hymenoptera, see 



by the length of the horny plates composing the Hartig; Die Adlerfliiger Deutschi. ]). 16 ; in 



ovipositor. JViegmatin\i Archiv, 1837, I. p. 151, and in 



4 For the structure of this saw-like ovipositor, Germar^s Zeitsch. III. p. 326 ; Ratzeburg, Mc- 



see Lijonet, Mem. du Mus. XIX. p. 57, PI. VI.- diz. Zool. II. p. 145, Taf. X.XIII. (Cynip."). F .r 



VIII. (14-16) (Mouches 4 scie) ; and Hartig, Die that of the Cicadidae, see Reaumur, Mem. V. 



Adlerfliigler Deutsclil. p. 37, Taf. I. u. d. f. ; also, 4 memoire, PI. XVIII. ; and Doyire, Ann. A. Sc. 



Reaumur, M^m. VI. 11 memoire, PI. XL. fig. 6- Nat. VII. 1837, p. 193. 



39 



