218 : FOOD OF INSECTS. 
Another numerous class kill their prey outright, either devouring its solid 
parts, as the predaceous and rove-beetles, &c., or imbibing its juices only, 
as the infinite hordes of the field-bug tribe. And the larve of the gnat, 
chameleon (Stratyomis), and other flies aquatic in that state, the leviathans 
of the world of animalcules, swallow whole hosts of these minute inhabj- 
tants of pools and ponds at a gulp, causing, with their oral apparatus, a 
vortex in the water, down which myriads of victims are incessantly hurried 
into their destructive maw. 
But not only animals themselves, almost every animal substance that can 
be named, is the appropriate food of some insect. Multitudes find a de- 
licious nutriment in excrements of various kinds. Matters apparently so 
indigestible as hair, wool and leather, are the sole food of many moths in 
the larva state (Tinea tapetzella, pellionella, &c.), Even feathers are not 
rejected by others ; and the grub of a beetle (Anthrenus Musaorum), with 
powers of stomach which the dyspeptic sufferer may envy, will live luxuri- 
ously upon horn,? 
For the most part, insects feeding upon animal substances will not touch 
vegetables, and vice versa. You must not, however, take the rule without 
exceptions. Many caterpillars (as those of Thyatira derasa, Chariclea 
Delphinii, &c.), though plants are their proper food, will occasionally de- 
vour other caterpillars, and sometimes even their own species. The large 
green grasshopper (Acrida viridissima), and probably others of the Order, 
will eat smaller insects as well as its usual vegetable food? ; so also will 
the larvae of many Phryganez. Allantus marginellus, as 1 was last summer 
amused by witnessing, like many Scalophage, sips the nectar of umbel- 
liferous plants only till a fly comes within its reach, pouncing upon which 
it gladly quits its vegetable for an animal repast. Anobium paniceum, which 
ordinarily feeds upon biscuit, was, as I have before mentioned, once found 
by Mr. Sheppard, in great abundance living upon the dried Cantharides 
(Cantharis vesicatoria) of the shops. On the other hand, Necrophorus 
mortuorum, which subsists on’ carcasses, and many other carnivorous 
species, will make a hearty meal of a putrid fungus. Ptinus Fur devours 
indifferently dried birds or plants, not refusing even tobacco; and from 
the impossibility that one of a million of the innumerable swarms of gnats 
which abound in swampy places, particularly in regions which but for them 
would be lost to sensitive existence, should ever taste blood, it seems clear 
that they are usually contented with vegetable aliment. Indeed the males, 
as well as those of the horse-fly, of which even the females readily imbibed 
the sugared fluid offered to them by Reaumur 8, never suck blood at all ; 
so that they must either feed on vegetable matter, which in fact I have 
observed them do, or fast during their whole existence in the perfect 
State. 
Though insects, generally considered, have thus a much more extensive 
bill of fare than the larger animals, each individual species is commonly 
limited to a more restricted diet. Many both of animal and vegetable 
feeders are absolutely confined to one kind of food, and cannot exist upon 
any other. The larva of G2strus Equi can subsist nowhere but in the 
stomach of the horse or ass ; which animals, therefore, this insect might 
boast with some show of reason to have been created for its use rather than 
1 De Geer, iv. 210, 2 Brahm, Znsekten Kalender, i. 190. 
5 Reaum. iy. 280, 
