GEOGRAPHICAL DISTRIBUTION OF INSECTs. 481] 
of the different Orders to each other. The Coleoptera 
may be stated as forming at least 1: 2 of our intire insect 
population; the Orthoptera and Dermaptera as about 
1: 160; the Hemiptera as 1:15; the Lepidoptera as more 
than 1: 4; the Newroptera with the Trichoptera as 1: 29; 
the Hymenoptera as about 1:43; the Diptera as not 1: 7; 
and the Aptera and Arachnida as perhaps amounting to 
Beato? 
To extend this inquiry to exotic and more particularly 
to extra-European insects, in the present state of our 
knowledge, would lead to no very satisfactory results. 
The lists we have are so imperfect, that those which tell 
most in this country,—1 mean the more minute insects 
and the Brachelytra Latr.,—have hitherto formed a very 
small, if any part, of the collections made owt of Eu- 
rope. Mr. W. S. MacLeay however, who, besides his 
father’s (particularly rich in Pefalocera), has had an op- 
portunity of examining the Parisian and other cabinets, 
finds that the species of coprophagous insects within the 
tropics, to those without, are nearly in the proportion of 
4:3; and that the coprophagous Petalocera, to the re- 
mainder of the saprophagous ones, may be represented by 
3:2. It may be inferred, from the superabundance of 
plants and animals in equinoctial countries, that the num- 
ber of species of insects in general is greater within than 
without the tropics: the additional momentum produced 
by the vast size of many of the tropical species must also 
be taken into consideration. 
II. There are three principal points that call for at- 
2 If we consider the number of species of Acari, Nirmi, Podure, 
and Araneide, this proportion will appear moderate. 
> Hor, Entomolog. 48. 
VOL. Iv. Zt 
