62 



BRANCH ARTHROPOD A. 



spider. This poison is of use in killing insects and other 

 small animals, and produces great pain and inflammation 



FIG. 98. 



Seal open' dra gigante'a. Centipede. (.) 



when inoculated into the human system. The larger 

 and more dangerous forms are found only in the warmer 

 countries. 



PIG. 99. 



CLASS HEXAPODA (hex ap'6 da) (INSECTA). 



The true INSECTS have the body divided into three 

 portions : the head, the thorax, and the abdomen. The 

 head bears a pair of large compound eyes, 

 and generally two or three simple eyes ; 

 attached movably to it, are four pairs of 

 appendages, from which fact we infer that 

 the head is composed of four segments 

 more or less consolidated. The first pair 

 of appendages is the antennae; next the 

 strong jtt/r*, behind which are the rnax- 



Head of Insect. Locust, 

 showing chief points 

 in its external anat- 



showing chief points .,-, (m&x Iri6) w i t h their polpi (pal'pT), 



omy. o, simple eye. anc ] finally the labium da'bi um), or lower 



E, Compound eye. A, 



Antenna. L, Upper Up also with palpi.* The thorax is com- 

 Hp. Jf, Jaw. MX, 



Maxiiia. Lb, Under posed of three segments, each bearing a 



lip. P, Palpus. . m-, 



pair of legs. The abdomen is usually 

 without appendages, and generally has ten segments. 



* These mouth-parts enter directly into the economy of the insect's life, and 

 are consequently of the greatest value as aids in classification. 



