SYSTEM OF INSECTS. 417 



lion and motion, in their ovipositor, and in the other 

 details of their structure a . 



I have on a former occasion pointed out many of the 

 analogies which take place between insects and other 

 parts of the animal kingdom, and even between insects 

 and the mineral and vegetable kingdoms 5 : I shall now 

 resume the subject more at large, but without recurring 

 to those last mentioned. In considering the analogies 

 which connect insects with other animals, or which they 

 exhibit witli respect to each other, we may have recourse 

 to two methods. We may either consider them as placed 

 somewhere between the two extremes of a convolving 

 series, from which station we may trace these analogies 

 upwards and downwards towards each limit ; or we may 

 conceive them and other animals in this respect arranged 

 in a number of series that are parallel to each other, in 

 which the opposite points are analogous. The first mode 

 will perhaps best explain the analogies that exist between 

 insects and other animals, and the last those between dif- 

 ferent groups of insects themselves. I shall give an ex- 

 ample or two of each method, beginning with the first. 



There are two tribes in the animal kingdom that seem 

 placed in contrast to each other, both by their habits and 

 by their structure. One of these is carnivorous, living 

 by rapine and bloodshed, and can seldom be rendered 

 subservient to our domestic purposes ; while the other is 

 herbivorous or granivorous, is quiet in its habits, and 

 easily domesticated. Amongst insects we find the re- 

 presentatives of both : those of the first tribe are distin- 

 guished by their predaceous habits, by the open attacks, 

 or by the various snares and artifices which they employ 



a Sec above, p. 382 . b VOL. I. p. 7 - . 



VOL. IV. 2 E 



