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INSECTA. 



ORDER I. APTERA. 



Insects without wings and without metamorphosis ; that is 

 to say, maintaining always the form in which they issue from 

 the egg. 



FAMILY I. MYRIAPODA. Centipedes. 



Body very much elongated and composed of a series of si- 

 milar annuli, each of which sustains one or two pairs of feet; 

 the number of the rings and feet augmenting with the age of 

 the animal ; abdomen not distinct from the thorax ; head pro- 

 vided with two eyes formed by an union of smooth ocelli 

 (little eggs) ; two antennae ; a mouth armed with jaws. They 

 live in the earth, and under different bodies placed upon its 

 surface. 



FAMILY IL PARASITA. 



Six feet only ; abdomen without articulated and movable 

 appendages ; two, or four, small smooth eyes ; a great portion 

 of the mouth internal, and exhibiting externally either a snout 

 or projecting mammilla, containing a retractile sucker, or two 

 membranous and approximated lips, with two hooked man- 

 dibles. Body flattened, transparent, divided into eleven or 

 twelve segments, of which three belong to the trunk, and 

 have each a pair of feet. They dwell constantly upon the 

 same Quadrupeds and Birds, whose blood they suck. So great 

 is their fecundity, that it has been calculated their females, in 

 two months, can give birth to eighteen thousand young. 

 Certain people, called Phtirophages, such as the Hottentots 

 and New Zealanders, eat these disgusting animals. 



Genus I. Pediculus, Deg. True Louse. 



Mouth exhibiting externally a very small mammilla, con- 

 taining a sucker. Tarsi composed of one articulation, almost 

 equal in size to the tibia, and terminated by a very stout nail, 

 folding over a projection, so as to form a kind of tooth, whose 

 office is that of a forceps. 



