Chapter 2 1 



COMMON INSECTS— GRASSHOPPER AND 

 HONEYBEE (PHYLUM ARTHROPODA; 

 CLASS INSECTA) 



GRASSHOPPER (figs. 191 to 194) 



Insects are air-breathing arthropods with bodies divided into head, 

 thorax, and segmented abdomen. The head bears one pair of antennae 

 and the thorax bears three pairs of jointed legs. The grasshopper is a 

 rather desirable type for study because it is large and less specialized than 

 many other types. Although there are many different species of grass- 

 hoppers which vary in certain respects, the following descriptions apply 

 in general to most species which are available for study: Grasshoppers 

 have enlarged hindlegs, sound-producing and sound-receiving structures, 

 leathery forewings, and membranous hindwings. On either side of the 

 head is a compound eye. On top of the head are simple eyes, called 

 ocelli (o-sel'i) (L, ocellus, little eye). Grasshoppers have chewing 

 mandibles (mandibulate mouth parts) which may be studied in Fig. 192. 

 Grasshoppers belong to the order Orthoptera (or -thop' ter a) (Gr. 

 orthos, straight; ptera, wings). 



Integument and Skeleton. — A flexible, noncellular, chitinous cuticle 

 also serves as an exoskeleton (ek so -skeF e ton) (Gr. exo, external; skele- 

 tos, hard) to which organs, muscles, ^and tissues are attached on the 

 inside. The cuticle is secreted by a cellular hypodermis beneath it. The 

 chitin chemically has the formula C30H50O19N4. Beneath the hypoder- 

 mis is a basement membrane. 



Internally the cavity in the body is not a true coelom but a hemocoel 

 (he'mosele) (Gr. haima, blood; koilos, hollow), being filled with or- 

 gans and a colorless blood. When the animal grows, it sheds its chitin 

 at intervals by the process of moulting or ecdysis (ek' di sis) (Gr. ekdyein, 

 to shed) . The liquid secreted by the hypodermis hardens into new chitin. 



Motion and Locomotion. — Grasshoppers may walk or jump by means 

 of the three pairs of jointed legs or fly by means of two pairs of wings. 



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