300 MOTIONS or INSECTS. 



touches the upper part of the cocoon, and tlie liead and 

 anus rest upon the lower), and strikes the upper part 

 "with the head and tail, before its belly, whicli then be- 

 comes the convex part, touches the bottom. This oc- 

 casions the cocoon to rise in the air to a height propor- 

 tioned to the force of the blow. At first sight this fa- 

 culty seems of no great use to an animal that is sus- 

 pended in the air ; but the winds may proba])ly some- 

 times place it in a diirerent and unsuitable position, 

 and lodge it upon a leaf or twig : in this case it has 

 it in its power to recover its natural station. Reau- 

 mur could not ascertain the fly that should legitimately 

 come from this cocoon, for different cocoons gave dif- 

 ferent flies : whence it was evident that these ich- 

 neumons were infested by their own parasite^. This 

 might be the case with that of the lady just mentioned. 

 Perhaps, properly speaking, in this last case the mo- 

 tions ought rather to be regarded as belonging to a 

 larva ; but as it had ceased feeding, and had inclosed 

 itself in its cocoon, 1 consider it as belonging to the 

 present head. 



You may probably here feel some curiosity to be in- 

 formed how the nuuierous larvcB that are buried in their 

 pupa state, either in the heart of trees, under the earth, 

 or in the waters, effect their escape from their various 

 prisons and become denizens of the air, especially as 

 you are aware that each is shrowded in a winding sheet 

 and cased in a coffin. In most, however, if you exa- 

 mine this coffin closely, you will see resurgam writ- 

 ten upon it. What I mean is this. The puparium or 

 case of the animal is furnished with certain acute points 



' Keaum. ii. 450, 



