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Classification of Insects and Mites. 



The Natural Group, which embraces both the bee 

 and its tracheal parasite, is known to science by the 

 name Arthropoda. The term signifies " jointed footed." 

 The group embraces more than half the known species 

 of living animals of the present day. Representative ex- 

 amples are : lobsters, crayfish, crabs, woodlice, water 

 fleas, all insects, centipedes, millipedes, spiders, 

 scorpions, mites, ticks, king crabs. Diverse as these 

 various creatures appear at first sight, they possess 

 certain fundamental characters in common, aiid the 

 group undoubtedly constitutes a natural branch of the 

 Animal Kingdom. It will be useful to enumerate some 

 of the most obvious features common to Arthropods 

 before distinguishing more particularly the two types 

 we are more immediately interested in, namely Insects 

 and Mites. Besides possessing paired jointed limbs, 

 Arthropods have a cuticular covering to the body, 

 composed of the substance chitin. It is the tough, 

 brownish, flexible substance we are familiar with, 

 covering the exterior of bees, cockroaches, beetles, 

 spiders, etc., or the transparent delicate "skin" upon 

 " water fleas ", or mites. A third character is shown 

 in the jointed or segmented body, well marked in such 

 forms as lobsters, crayfish, centipedes, caterpillars, bees ; 

 and less clearly in spiders and mites. Arthropods 

 further have a brain which is connected, by a nerve 

 loop enveloping the forepart of the alimentary canal, to 

 a chain of nerve centres running down the under-side of 

 the body beneath the skin in the middle line. 



Two important classes within the Arthropod Phylum 

 are the Insecta and the Arachnida, which without for- 

 getting that they have in common the characters 

 enumerated above, we may here conveniently contrast 

 in tabular form. 



Insecta. Arachnida. 



Possessing Antennae. Without Antennae. 



Compound eyes usual. Never with compound eyes- 



Three pairs of mouth appen- Two pairs of appendages at 

 dages or jaws. mouth — not exclusively 



jaws. 



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