n between parts which results from their
development from corresponding embryonic parts, either in different
animals, as in the case of the arm of man, the fore-leg of a quadruped,
and the wing of a bird; or in the same individual, as in the case of the
fore and hind legs in quadrupeds, and the segments or rings and their
appendages of which the body of a worm, a centipede, etc., is composed.
The latter is called serial homology. The parts which stand in such a
relation to each other are said to be homologous, and one such part
or organ is called the homologue of the other. In different plants
the parts of the flower are homologous, and in general these parts are
regarded as homologous with leaves.

HOMOPTERA.--An order or sub-order of insects having (like the Hemiptera)
a jointed beak, but in which the fore-wings are either wholly membranous
or wholly leathery, The Cicadae, frog-hoppers, and Aphides, are
well-known examples.

HYBRID.--The offspring of the union of two distinct species.

HYMENOPTERA.--An order of insects possessing biting jaws and usually
four membranous wings in which there are a few veins. Bees and wasps are
familiar examples of this group.

HYPERTROPHIED.--Excessively developed.

ICHNEUMONIDAE.--A family of hymenopterous insects, the members of which
lay their eggs in the bodies or eggs of other insects.

IMAGO.--The perfect (generally winged) reproductive state of an insect.

INDIGENES.--The aboriginal animal or vegetable inhabitants of a country
or region.

INFLORESCENCE.--The mode of arrangement of the flowers of plants.

INFUSORIA.--A class of microscopic animalcules, so called from their
having originally been observed in infusions of vegetable matters. They
consist of a gelatinous material enclosed in a delicate membrane, the
whole or part of which is furnished with short vibrating hairs (called
cilia), by means of which the animalcules swim through the water or
convey the minute particles of their food to the orifice of the mouth.

INSECTIVOROUS.--Feeding on insects.

INVERTEBRATA, or INVERTEBRATE ANIMALS.--Those animals which do not
possess a backbone or spinal column.

LACUNAE.--Spaces left among the tissues in some of the lower animals
and serving in place of vessels for the circulation of the fluids of the
body.

LAMELLATED.--Furnished with lamellae or little plates.

LARVA (pl. LARVAE).--The first condition of an insect at its issuing
from the egg, when it is usually in t