258 ZOOLOGY 



kite until it catches some projection, when the spider hauls in the slack, 

 makes it fast, and travels across on the slender bridge thus built. 



Myriapods. — We are all familiar with the harmless and common 

 thousand legs found under stones and logs. It is a representative 

 of the group of animals known as the millepeds. These animals 

 have the body divided into two regions, head and trunk. They 

 have two pairs of legs for each body segment. The centipeds, on 

 the other hand, have only one pair of legs to each segment. None 

 of the forms in the eastern part of the United States are poisonous. 



Classification of Arthropoda 



Class, Crustacea. Arthropods with limy and chitinous exoskeleton, breathing by 



gills, and having two pairs of antennae. 

 Subclass I. Eniomostraca. Crustacea with a variable niimber of segments, 



chiefly small forms with simple appendages. Some degenerate or parasitic. 



Examples, barnacles, water flea (Daphnia), and copepods (Cyclops). 

 Subclass II. Malacostraca. Usually large Crustacea ha\ang nineteen pairs 



of appendages. Examples, American lobster (Homarus americanus) , crab 



(Cancer), or shrimp (Paloemonetes) . 

 Class, Hexapoda (insects). Arthropoda having chitinous exoskeleton, breathing 



by air tubes (tracheae), and having three distinct body regions. 

 Order, Aptera (without wings). Several wingless forms. Examples, springtails. 

 Order, Orthoptera (straight wings). Example, Rockj^ Mountain locust. 

 Order, Lepidoptera (scale wings). Examples, cabbage butterfly, cecropia moth. 

 Order, Diptera (two wings). Examples, house flj', mosquito. 

 Order, Hemiptera (half wing). Examples, all true bugs, plant lice, and cicada. 

 Order, Neuroptera (nerve wings). Examples, May fly, dragon fly. 

 Order, Coleoptera (shield wings). Examples, beetles. 

 Order, Hymenoptera (membrane wings). Examples, bees, wasps, ants. 

 Class, Arachnida. Arthropoda with head and thorax fused. Six pairs of 



appendages. No antennae. Breathing by both lungs (spiders) or tracheae. 



Examples, spiders and scorpions. 

 Class, Myriapoda. Arthropoda, having long bodies with many segments ; 



one or two pairs of appendages to each segment. Breathing by means of 



tracheae. Example, centiped. 



Referexck Books 



FOR THE PUPIli 



Needham, Outdoor Studies, American Book Company. 



FOR THE TEACHER 



Emerton, The Structure and Habits of Spiders. Knight and Millet. 



