THE WORD INSECT. 19 



brain, no veins, no branched arteries, consequently no 

 circulating blood ; and do not breathe by the mouth, 

 but through air-pipes in the sides. All insects have 

 exactly six legs, though some butterflies have the 

 first pair so short as not to be readily observed; and 

 many caterpillars have, besides their six legs, as 

 many as ten to sixteen members similar to legs, for 

 the purpose of clinging and climbing. 



B 2 



