66 STATES OF INSECTS. 



to other circumstances connected with the subject, ar- 

 ranged for the sake of order under several distinct heads, 

 as — their exclusion — situation — substance — number — size 

 —figure — colour — and period of hatching. 



i. Exclusion. The exclusion or extrusion of the im- 

 pregnated eggs takes place, when, passing from the ovary 

 into the oviduct, they are conducted by means of the 

 ovipositor, in which it terminates, to their proper situa- 

 tion. By far the greater number of insects extrude them 

 singly, a longer interval elapsing between the passage of 

 each egg in some than in others. In those tribes which 

 place their eggs in groups, such as most butterflies and 

 moths, and many beetles, they pass from the ovaries 

 usually with great rapidity ; while in the Ichneumonida?, 

 Sphegidce, (Estri, and other parasitic genera, which usu- 

 ally deposit their eggs singly, an interval of some minutes, 

 hours, or perhaps even days, intervenes between the ex- 

 trusion of each egg. One remarkable instance of the 

 former mode I noticed in my letter on the Perfect Socie- 

 ties of Insects 3 ; another may be cited, to which you may 

 yourself be a witness — I allude to that common moth, 

 vulgarly called the Ghost (Hepialus Humuli), which lays 

 a large number of minute black eggs, resembling grains 

 of gunpowder, and ejects them so fast that, according to 

 De Geer, they may be said to run from the oviduct, and 

 are sometimes expelled with the force of a popgun b . A 

 Tetrapterous insect, the genus of which is uncertain, is 

 said, when it is taken, to discharge its eggs like shot from 

 a gun c . And a friend of mine, who had observed with at- 

 tention the proceedings of a common crane-fly ( Tipida), 



a See Vol. II. p. 36. b De Geer i. 494—. 



e Called by M. l'Abbe Preaux, who observed it near Lisieux in 

 Normandy, Mouche Batiste. N. Diet. cV Hist. Nat. xxi. 442. 



