216 SALMONIA. 



and I have not the knowledge, or if I had, 

 the time, to go through the lists of these 

 interesting little animals ; but of the family of 

 one of them I must speak the ichneumons, 

 that deposit their eggs in caterpillars, or the 

 larvae of other flies, and which feed on the 

 unfortunate animals on which they are 

 hatched, and come out of its interior when 

 dead, as if it had been their parent. To 

 enter into the philosophy of this subject, and 

 to study the organs and faculties of these 

 various insect tribes, in their functions of 

 respiration, nutrition, and reproduction, 

 would be sufficient for the labour of a life. 

 To know what has already been done would 

 demand the close and studious application 

 of a comprehensive mind; and to complete 

 this department of science in all its parts, is 

 probably almost above human powers, but 

 much might be done if enlightened persons 

 would follow the example of De Geer, 

 Reaumer, and Huber, and study minutely 

 the habits of particular tribes ; and it is pro- 

 bable that physiology might be much ad- 

 vanced by minutely investigating the simplest 



