MUSCULAR ACTIVITY 



63 



of them complete? The end of the abdomen is modified in the female 

 into an ovipositor or egg layer (see diagram). 



On each side of the abdomen in eight of the segments (in the red- 

 legged grasshopper) are found tiny openings called spiracles. There 

 are also two pairs of spiracles on the thorax. These spiracles open into 

 little tubes called tracheae (tra/ke-e). The tracheae divide and subdi- 

 vide like the branches of a tree, so that all parts of the body cavity are 

 reached by their fine endings. Is there any movement of the abdomen 

 of the living grasshopper? Describe this movement. Air is drawn in 

 by the expansion of the abdomen and forced out when it contracts. 

 By means of the tracheae, air is brought in contact with the blood. 



Muscular activity. Insects have the most powerful muscles of 

 any animals of their size. Relatively, an enormous amount of 

 energy is released during jumping or flying. The tracheae pass 

 directly into the muscles and other tissues so that a supply of 

 oxygen is directly at the place where energy is being released. 



.Simple Compound 



6in$e unit of 

 compound 

 eye of worker 

 laonejrloee^ 



lov^er lip 

 Find the knife and fork of the grasshopper. 



liboffemeftt 

 r"TneTn.torwie, 

 L. nerve fiber 



What two insect heads are shown here ? 

 Read your text carefully. 



Food taking. The grasshopper is provided with two pairs of 

 jaws, a fork-like pair, the maxillae (mak-sil'e), and a pair of hard 

 toothed jaws, the mandibles. These parts when not in use are 



