448 $ 348. 
THE INSECTA. 
the anus. This duct has several double or single appendages, of which. 
one with the females serves as a seminal receptacle (Receptaculum seminis),. 
or as a copulatory organ (Bursa copulatrix), while the others, in both 
sexes, are true secretory organs. The vagina is often prolonged into a 
horny ovipositor, and this same organ modified, with the males, is the Penis. 
The Eggs of Insecta are very varied in their forms and colors. Exter- 
nally, they are frequently marked by prominences and raised lines, forming 
a very varied, and often a very elégant design.” Those of some Cynipi- 
dae, Ichneumonidae, and Siricidae, have one of their ends prolonged into a 
long, straight or curved thread.© With some Hydrocorisae they are oblong 
and their posterior extremity is covered with long. stiff bristles.” They 
have, usually, a very solid chorion, and a thin vitelline membrane. The 
vitellus is composed of fat-vesicles more or less colored, which communicate 
their color to the entire egg. The germinative vesicle contains a germina- 
tive dot which is often composed of several parts. 
These eggs are formed after two different types. 
1. With the Orthoptera, and various Coleoptera, the germinative vesicle 
is formed in the posterior extremity of the tubular ovaries, and is gradu- 
ally surrounded by a mass of granular vitelline substance. This vitelline 
mass continues to increase until, at last, there is formed on its surface a 
chorion, at first soft, but which finally becomes solid. During the course 
of this development, the eggs succeed each other in a row, and in this way 
advance towards the opening of the ovarian tube. 
2. With the Lepidoptera, Diptera, Hyménoptera, Neuroptera, Cicindeli- 
dae, Carabidae, and Hydrocanthari, the mode of formation is wholly differ- 
ent. The vitelline mass which is disposed around the germinative vesicle, 
increases in the fellowing manner: Between each two vitelline masses, 
there appear a group of large vitelline cells whose contents are blended: 
with the subjacent vitelline mass; while, thé chorion is developed from a. 
layer of vitelline cells, commencing by its inner portion. It gradually 
extends over the vitelline mass and cells, and finally, when the vitellus has 
reached a certain volume, closes at the upper portion of this last. The 
epoch at which the eggs reach their maturity coincides, with the Lepidop- 
tera, Tipulidae, and Kphemeridae, with the end of their pupa state, so that 
these insects are able to deposit their eggs as soon as they have cast off 
their pupa envelope; while, with the Libellulidae, the Locustidae, and 
especially the Apidae, the eggs are not matured in the ovaries until a long 
time after.“ 
With all Insecta, the sperm contains very active filiform spermatic: 
particles which become immediately stiff and looped when put in water. 
These particles are developed in large cells whose involucrum finally dis- 
5 Kirby and Spence (Kinleitung, &c., p. 100, Taf. 
XV.) have figured a great nuinber of eggs of insects of 
various forms, See, also, Burmeister, Handb. &c. 
Taf. I. and Lacordaire, Introduction, &c., Pl. I. 
6 See L. Dufour, Recherch. sur les Orthopt. fig. 
128, 149 (Cynips and Xiphydria); Hartig, in 
Wiegmann’s Arch. 1837, I. p. 151, Taf. 1V. (Try- 
phon, Paniscus, and other Ichneumonidae), and 
in Germar’s Zeitsch, f. Entom. p. 327, Taf. I. tig. 
5, 6 (Cynips). 
7 The eggs of Ranatra have two long bristles ; 
while, with those of Vepa, these last form a coro- 
net; see Roese/, Insektenbelust. III. Taf. XXIT. 
XXIIL., and L. Dufour, Revherch. sur les Hé- 
Inipt. Pl. XVI. 
8 See Wagner, Prodromus, &c., p. 9, Tab. II. 
fig. 18-22. 
9 See Wagner, Abhandl. d. physical. mathemat. 
Klasse. der Akad. zu Munich, IT. 1837, p. 554, 
Taf. II. fig. 1 (Agrion), and Stein, Vergl. Anat. 
u. Physiol. d. Insekt. [. p. 47, Taf. LX. fig. 4, & 
(Telepkorus and Acheta). 
10 Herold was the first who observed this re~ 
markable mode of the formation of the eggs with 
the Lepidoptera ; see his Disquisit. &c. Tab. I. fig. 
11-18, or Ann. d. Sc. Nat. XII. 1839, p. 195, Ph 
VII. fig. 13-18. Researches even still more de 
tailed have been made by Stein, Vergl. Anat. &c. 
p- a Taf IX fig. 2, 9,13 (Bontea and Pterosta 
chus 
