498 
GEOGRAPHICAL ZOOLOGY. 
[PART IV. 
LONGICOJLNTA. (1,488 Genera, 7,576 Species). 
The elegant and admired group of the Longicorn Beetles, is 
treated by continental authors as a single family, consisting of 
three sub-divisions — the Prionidse, Cerambycidoe, and Lamiidoe 
of English entomologists. These are so closely related, and are 
so similar in form, habits, and general distribution, that it will 
be best to consider the whole as one group, noticing whatever 
peculiarities occur in the separate divisions. The endless 
structural differences among these insects, have led to their 
being classed in, an unusual number of genera, which average 
little more than 5 species each ; a number far below that in any 
of the other families we have been considering, and probably 
below that which obtains in any of the more extensive groups 
of animals or plants. This excessive subdivision of the genera, 
a large number of which consist of only one or two species, 
renders it difficult to determine with precision the relations of 
the several regions, since the affinities of these genera for each 
other are in many cases undetermined. A group of such 
enormous extent as this, can only be properly understood after 
years of laborious study ; we must therefore content ourselves 
with such results as may be obtained from a general survey of 
the group, and from a comparison of the range of the several 
genera, by means of a careful tabulation of the mass of details 
given in the recent Catalogue of Messrs. Gemminger and Harold 
and the noble work of Lacordaire. 
The proportionate extent of the three families of Longicorns is 
very unequal ; the Prionidoe comprising about 7 per cent., the 
Cerambycidoe 44 per cent., and the Lamiidoe 49 per cent, of the 
total number of species ; and the genera are nearly in the same 
proportions, being almost exactly 10, 40, and 50 per cent, of the 
whole, respectively ; or, 135 Prionidse, 609 Cerambycidoe, and 746 
Lambda). The several regions, however, present marked differ- 
ences in their proportions of these families. In the two North 
Temperate regions, the Cerambycidoe are considerably more 
numerous than the Lamiidoe, in the proportion of about 12 to 
