SYSTEM OF INSECTS. 395 
vi. I need not say more on those larger groups of an 
Order which conduct us to what are denominated its 
genera; but upon these last it will not be a waste of your 
time to enlarge a little. In the last edition of the Sy- 
stema Nature, and in its appendixes, Linné has described. 
2840 species of Znsecta and Arachnida, which he divided 
into 83 genera, allowing upon an ayerage nearly 35 
species to each genus. [From the paucity of the mate- 
rials, therefore, of which his system was constructed, 
there was no loud call upon him for numerous genera. 
But now more than thirty times that number are said to 
have found a place in the cabinets of collectors*, and 
there is good reason for thinking that perhaps half that 
are in existence are as yet undiscovered ;—this makes 
it a matter of absolute necessity to subdivide the Linnean 
genera, which in fact, with regard to the majority of them, 
were the primary groups of his Orders, rather than an 
approximation to the ztzmate. But this principle may 
be carried too far: for it is the nature of man to pass 
from one extreme to the other: and this seems to me to 
be the case when it is proposed to make genera the ea- 
treme term of subdivision before you arrive at species. 
But it is argued by a very acute Zoologist, that sumplicity, 
perspicuity, and room for necessary variations. are best 
preserved by distinguishing these subdivisions each by 
an appropriate name> :—Granted. But still it is only a 
choice of evils. It would require probably more than 
10,000 names to designate them, were every extreme 
group distinguished by a name: but if Mr. MacLeay’s 
« Mr. MacLeay says‘that more than 100,000. Annulosa exist in 
collections.— Hor. Ent. 469. 
® Vigors in Zoolog, Journ. I. ii. 188. 
