CHAP. 1. 1 DEFINITION AND STRUCTURE OF [NSE( rS 9 



jumping legs of grasshoppers, the modification of the structure of 

 legs to accord with swimming, burrowing or raptorial habits, and 

 the peculiar legs of bees which arc used tor the collection and 



transport of pollen. 



The legs, though primarily used tor the purpose oi walking. 

 occasionally assume other functions, such as tactile organs. The 

 manner in which Mosquitos hold up their hindlegs to detect the 

 approach ot .m\ danger is well known to everybody, whilst other 

 insects (Chironomidae, Micropezidae) use their forelegs in somewhat 

 the same manner. The legs may also be used tor stridulatory 

 purposes, as in many grasshoppers, or may contain auditory- 

 organs, as in the Phasgonuridae. 



Stenodictya lobata,s ( arboniferous Insect, showing prothoracic lob< s. 

 I hi left i ai il. that on thi 



i) 1 [andlirsch. i After Berlese.l 



The wings are placed as a rule on the upper surface of the two 

 posterio ts of the thorax, but either or both pairs are not 



infrequentlj obsolescent or quite absent- In the earliest ins 

 is probable thai three pairs of wings were originally present, traces 

 of a pair of prothoracic wings being seen in some of the earliest 

 known fossil insects such as Stenodictya lobtita, which lived millions 

 ot years ago in the Carboniferous Epoch. But even at the present 



FlG. 10. — An immature Sinhalese I'enniti Arrhinotermes flavus), 2*5 nun. 

 Inn;,', bearing rudimentary prothoracic wine-. c-\ftor Bugnion.) 



