GLOSSARY 459 



in the case of the fore and hind legs in quadrupeds, and the seg- 

 ments 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 homol- 

 ogous, and in general these parts are regarded as homologous with 

 leaves. 



HoMOPTERA. — ^An order or sub-order of Insects having (like tlie 

 Hemiptera) a jointed beak, but in which the fore-wings are either 

 wholly membranous or wholly leathery. The Cicada, Frog-hop- 

 pers, and Aphides, are well-known examples. 



Hybrid. — The offspring of the union or two distinct species. 



Hymenoptera. — An order of Insects possessing biting jaws and usu- 

 ally four membranous wings in which there are a few veins. Bees 

 and Wasps are familiar examples of this group. 



Hypertrophied. — Excessively developed. 



IcHNEUMONiD^. — ^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 in- 

 sect. 



Indigens. — The aboriginal animal or vegetable inhabitants of a coun- 

 try 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 mem- 

 brane, the whole or part of which is furnished with short vibrating 

 hairs (called ciha), 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 lemellae or little plates. 

 Larva (pi. Larvae). — ^The first condition of an insect at its issuing from 



the egg, when it is usually in the form of a grub, caterpillar or 



maggot. 



