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which contain air tubes, etc. The neuration of the 

 wings is important in identifying insects. The wings 

 are frequently much modified, for instance in a beetle, 

 the front pair are hard, horny structures ( = elytra). 



The legs are attached to the lower part of the thorax ; 

 they are either six or absent ( = apodal insects). Each 

 pair is united to a thoracic ring, the first are pro-thoracic 

 legs, the second meso-thoracic, and the hind pair are 

 meta-thoracic legs. The legs are jointed and are normally 

 made up of nine segments ; the basal one is the coxa, 

 this is followed by a small segment, the trochanter, then 

 the long femur, and the tibia or shank, lastly the foot or 

 tarsus, which is composed of from one to five segments. 

 The last tarsal segment ends in two claws or ungues, 

 which have between them differently shaped structures 

 called pulvilli or pads, etc. There is much modification 

 in insects legs, some are long and thin and adapted for 

 running (Tiger beetles), others have them broadened and 

 adapted to scraping in the soil (Mole Cricket), others for 

 jumping (Grasshoppers and Locusts), yet others for 

 swimming (Water-boatmen). The abdomen is composed 

 of a varied number of rings or segments each segment 

 having an upper and lower moiety, united by a soft 

 membrane, thus enabling the expansion of the abdomen ; 

 there are soft areas also between the segments. No 

 traces of organs of locomotion can be found on the 

 abdomen, but it terminates in varied structures, such as 

 a long egg-tube or ovipositor in some females (Ichneumon 

 Flies), a sting (Bees and Wasps), or in the males in 

 distinct clasper-like external sexual appendages. At the 

 sides of the abdomen and thorax we find a series of slit- 

 like openings ; these are called spiracles. 



