ICH 
occasioned by the melting ol Some of the 
ice. When tiie ice is put into the well, if a 
little saltpetre be mixed with it at every ten 
inches or a foot in thickness, it will cause it 
to unite more closely into a solid mass. 
ICH DIEN, the motto of the Prince of 
Wales’s arms, signifying, in the High Dutch, 
« I serve.” It was first used by Edward 
the Black Prince, to shew his subjection to 
his father King Edward III. 
ICHNEUMON, in natural history, a 
genus of insects of the Hymenoptera order : 
mouth with a straight horny membrana- 
ceous bifid jaw, the tip rounded and ciliate ; 
mandibles curved sharp ; lip cylindrical, 
membranaceous at the tip and emarginate; 
feelers four, unequal, filiform, seated in the 
middle of the lip; antennae setaceous, of 
more than thirty articulations; sting ex- 
erted, inclosed in cylindrical sheath, com- 
posed of two valves, and 'not very pungent. 
There are more than five hundred species 
enumerated by different authors. Ihese 
are separated into families. A. scutel, 
white or yellow ; antennae annulate with 
white. B. scutel, white or yellow ; anten- 
nae entirely black. C. scutel, the colour of 
the thorax; antennae ann&late. D. scutel, 
the colour of the thorax; antennae black. 
E. antennae yellow. P. minute ; antennae 
filiform ; abdomen sessile, ovate. 
The whole of this singular gemis have 
been denominated parasitical, on account 
of tiie very extraordinary manner in which 
they provide for the future support of their 
offspring. The fly feeds on the honey of 
flowers, and when about to lay her eggs, 
perforates the body of some other insect, 
or its larva, with its sting or instrument at 
the end of the abdomen, and there de- 
posits them. These eggs in a few days 
hatch ; and the young larva, which re- 
semble minute white maggots nourish them- 
selves with the juices of their foster parent, 
which however continues to move about 
. and feed till near the time of its change to 
a chrysalis, when the larva of the ichneumon 
creep out by perforating the skin in various 
places, and eacli spinning itself np in a 
small oval silken case, changes into a chry- 
salis, and after a certain period they emerge 
in the state of complete ichneumons. 
I. glomeratus, may be given as an exam- 
ple of this process. The caterpillar of the 
common white or cabbage butterfly, which, 
in the autumnal season, may be observed to 
creep up some wall, &c. in order to under- 
go its own change into a chrysalis ; but in 
the space of a day or two, a numerous tribe 
ICH 
of small maggots will be seen to emerge 
from it, and immediately proceed to enve- 
lope themselves in distinct yellow, silken 
cases, the whole forming a group round the 
caterpillar. These are the ichneumons glo- 
meratus : they are black, with yellow legs, 
and they usually make their appearance in 
about three weeks from the time of their 
spinning themselves up. Some of the ich- 
neumon genus pierce the skins of newly- 
changed chrysalises of butterflies and moths, 
in which their larva remain during their 
own incomplete state. Others are so mi- 
nute, that the female pierces even the eggs 
of moths and butterflies, and deposits her 
own in each. I. seductor, has a yellow 
scutel ; tip and petiole of the abdomen and 
crenate band on the fore-part yellow ; legs 
mostly yellow'. This insect is found chiefly 
in Pavia ; it forms a nest of cemented clay, 
in chimneys and windows, divided into cy- 
lindrical cells, in each of which is contained e 
a cylindrical, brown, lucid follicle, and in 
this the larva, with frequently the carcase of 
a spider, in which the insect had deposited 
her eggs. 
ICHN OGRAPHY, in perspective, the 
view of any thing cut off by a plane pa- 
rallel to the horizon, just at the base of it. 
Ichn ography, in architecture, a de- 
scription or draught of the platform or 
ground-work of a house, or other building. 
Or it is the geometrical plan or platform of 
an edifice or house, or the ground work of 
an house or building, delineated upon pa- 
per, describing the form of the several 
apartments, rooms, windows, chimnies, &c. 
Ichnography, in fortification, denotes 
the plan or representation of the length and 
breadth of a fortress, the distinct parts of 
which are marked out, either on the ground 
itself, or on paper. 
ICHTHYOCOLLA, .See Isinglass. 
ICHTHYOLOGY, is that part of natu- 
ral history that treats of fishes. And fishes 
are animals having a heart with one auricle 
and one ventricle, with cold red bl«od, 
which inhabit water, and breathe by means 
of gills. Most of the species are likewise 
distinguished by fins and scales. Different 
naturalists have given different systems, we 
shall briefly notice some of the principal, 
because we find them perpetually referred 
to in works of importance. Aldrovandus, 
about two hundred years ago, distributed 
the fishes according to the nature of their 
residence. His first book treats of those 
that frequent rocks ; the second is devoted 
to those found near the shores, called litto- 
