FORM AND COLOUR. 



distinctions only. Females are in some cases wingless. In flies 

 there are seldom striking differences ; male mosquitoes have large 

 feathery antennae, females smaller ones (fig. GO). Bugs are rarely dis- 

 tinguishable, but some of the 

 predaceous species have 

 clearly distinct sexes. In 

 Aphides, males are often 

 absent ; in Mealy Bugs and 

 Scale Insects, the male alone 

 is winged, the female wing- 

 less and degraded. 



Male insects commonly 

 produce sounds or songs. 

 Grasshoppers chirp by rub- 

 bing the hind leg along the 

 front wing ; green grass- 

 hoppers have a powerful 

 sound-producing apparatus 

 at the base of the wings. 

 Crickets produce a shrill loud noise. All of these insects also have 

 ears with which to hear the music they produce. Beetles have a very 

 great diversity of apparatus for producing sounds. The best known 

 noisy insects are the Cicadas which live in forests ; they are possessed 



FIG. 57. 

 Female Stag Beetle. 



FIG. 58. 

 Male Butterfly. 



