THE STRATIOMYS. 363 



and Nature has endowed it with an admirable pro- 

 vision for enabling it to take its ease in this position. 

 The only breathing-pore in the creature's body is 

 situated at the very extremity of its tail, and sur- 

 rounded by a beautiful coronet of fringed hairs, which 

 when expanded at the surface of the water, effectually 

 prevent that fluid from finding its way into the respi- 

 ratory tubes, and thus at the same time keep up a free 

 communication with the external air, and serve as a 

 sort of float to support their owner at the surface. 

 When the larva wishes to quit the surface, it folds-in 

 the coronet of hairs, which then entangle a small 

 bubble of air, and this either serves for a short time 

 for respiration, or merely to keep the water from 

 making its way into the tracheae. It is generally said 

 to be instrumental in enabling the creature to rise 

 again to the surface, but this can hardly be the case. 

 At the extremity of the body opposite to this beautiful 

 respiratory apparatus is the mouth, the parts of which 

 are small ; and the food is supposed to consist of mi- 

 nute aquatic animals, carried to the mouth by a sort 

 of vortex produced by the action of fine hairs attached 

 to the palpi. 



When full grown, the larva of Stratiomys chamodeon 

 measures about an inch and a half in length, and is 

 of a dull pale brown colour. It does not quit the 

 water to undergo its change to the pupa state, nor 

 does it retain any activity, but the pupa is formed in 

 the thickest portion of the larva, the skin of which 

 then hardens and forms a firm case for the protection 

 of the sleeping inmate, but still retains exactly its 

 original form. This, then, is the first example of a 

 coarctate pupa with which we have hitherto met, and 

 this form of the metamorphosis is common to the 



