FIELD BOOK OF INSECTS. 



CHIEFLY ABOUT SPIDERS 



Animals ha-ving no backbone but jointed 

 Classes of legs are ca ji e d Arthropoda. Some of these 



have two pairs of antennas, ("feelers") and 

 at least five pairs of legs; these are Crustacea and include 

 lobsters, crabs, crayfish, sow-bugs, and the like. Some 

 have no apparent antennas; one class of these live in the 

 sea (the "king"- or "horseshoe crab") and another is, 

 for the most part, terrestrial, breathing air. The latter 

 class is called Arachnida and includes spiders and their 

 relatives. Finally, there are three classes the members of 

 which have one pair of antennas. Two of them have more 

 than three pairs of legs and no wings: the Diplopoda, or 

 millipedes, have two pairs of legs on each of some, at least, 

 of their body segments; the Chilopoda, or centipedes, 

 have only one pair of legs to a single segment. The third 

 class is Hexapoda, or insects; when adult, they never 

 have more than three pairs of legs but usually have 

 wings. 



Some of the relatives of spiders have the 

 abdomen distinctly segmented; if there is a 

 tail-like hind end, it is a scorpion of some sort ; if not, it is, in 

 northeastern United States, either one of the small pseudo- 

 scorpions or else a " harvestman, " also called "grand- 

 father-graybeard, " "daddy-long-legs," etc., the creature 

 some of us used to deprive of most of its legs in order that 

 it should point the way to our cows or to our home. 

 Mites and spiders have unsegmented abdomens; mites 

 have no constriction of the body between the abdomen and 

 the leg-bearing portion, but spiders do. 



Many of the not-yet-acquainted consider 

 spiders to be insects and for that reason 

 they are mentioned here but briefly, because they have 

 no more claim to be considered insects than have lobsters, 

 except that they approach insects in the matter of in- 

 teresting habits: home building, prey catching, mating, 

 care of offspring, devices to escape their enemies, and the 



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