42 XLEMEXTS OF rNTOMOLOGY. 



Tnc opening through which they pass is.ahvays at the same part oftlie 

 skin, a Uttle above the trunk, bet\veen the wings and a snjall piece 

 which covers the head : different fissures are generally made in the 

 .same direction. When the operation begins, there seems to be a vio- 

 lent agitation in the humours contained in the little animal; the fluids 

 being driven with rapidity through all the vessels, the limbs and various 

 ])arts of tlie body are put in motion, and by repeated efforts it breaks 

 through the brittle skin that envelopes it. Those inclosed in cones or 

 cases, after bursting through the pupa covering, have another difliculty 

 to overcome, that of piercing through the inclosure, which in many 

 instances is of a stronger texture than the case of the pupa. For the 

 accomplishment of this, most insects arc provided with a liquor, which 

 they discharge from the mouth upon that part of the cone through 

 which they intend to esca'pe; and this so moistens and weakens it, that 

 after a short time they force their passage through with some facility. 

 Some insects not provided with this tluid leave one end of their cone 

 weaker than the rest, and close it only with a few threads, so that a 

 slight effort of the head enables the insect to burst from its prison. 



The butterfly or moth on emerging from the pupa is moist, the ab- 

 domen swollen, the antennaj bent down, and the wings crumpled, 

 small, and shapeless. These parts are gradually unfoldcil, and assume 

 their destined form. The wings, which at one instant are small and 

 like four little buds at the sides of the thorax, in a few minutes after 

 acquire their full size ; and the fibres, which were at first flexible, be- 

 come hard and rigid like bone. In proportion as the fibres lose their 

 flexibility, the fluids which circulate within them extend, and the wings 

 cease to act; so that, if any extraneous circumstance arrests the progress 

 of this fluid througii the fibres at the first instant of the moth's escape, 

 the wings immediately become crippled, and never afterwards assume 

 any other form. Most insects, soon after they have attained their per- 

 fect state, void an excrementitious substance, which in some places, 

 where the insects were abundant, has produced reports of showers of 

 blood. 



Of the IMAGO or Pnfcct Slate. As the present work is not in- 

 tended to enter into all the particulars relative to the habitat iom, foud, 

 modes of life, 4-c. I must refer the student to ]\hssrs. Kirbij and Spence's 

 popvdar intiviluction, in which much information on these points will 

 be found collected togetlier. 



