SOME SOUTH INDIAN INSECTS, ETC. 



I 11 W. I 



Of these phyla by far the raosl numerous at the present daj is 

 that of the Arthropoda, ;i name derived from two Greek words 

 meaning "jointed feet " and applied to these animals because the 

 appendages of the body arc composed of segments jointed to one 

 another. More than half a million different kinds of animals, of 

 which accurate descriptions have been published, belong to this 

 single phylum. 



The Arthropoda are sub-divided into tin' Crustacea 'Crabs. 

 Lobsters, Shrimps, Water-lit. is. etc.), the Arachnida (Scorpions, 

 Spiders and Mites), and the Hexapoda or [nsecta (Insects), and it 

 is to the study of this last group that we apply the term Entomo- 

 logy, a word derived from two (Ireek words meaning "insect 

 discourse." 



The word "insect" itself, both in its Creek and Latin forms. 

 signifies "something cut into" and is applied to these animals, 

 because the body as a whole is divided by two constrictions into 

 the three separate divisions of head, thorax and abdomen. The 

 name Hexapoda (" six-footed ") is applied to this group, because tin- 

 true insects are provided with not more than three pairs of legs. 

 Spiders, Scorpions, Ticks and Mites, which are often popularly 

 called " insects," differ from true insects by having' the head and 

 thorax fused together to form a cephalothorax and by possessing 

 it than three pairs of legs in the adult state. 



In a typical 

 insect the head 

 is provided with 

 paired mouth- 

 parts, com- 

 pound eyes 

 each composed 

 nt a large num- 

 ber of facets, 

 and antennae 



each composed 



of several or 



many joints, 

 and simple 



eves (ocelli) 



which are often 

 both paired and 

 unpaired. The 



thorax, which is itself composed of three segments (pro-, meso-, and 

 metathorax, reckoning from the head tailwards) bears three pairs 



I [G. I . — Simple external anatomy ol an insect 



i era tubus <. k Iriginal.) 



