SEX. 4 



In many Hymenoptera the sexes are very distinct. In the social insects 

 this is carried to a great extreme and we find only a small number of 

 individuals with reproductive organs, the majority being sexless workers 

 (figs. 51 and 55). In solitary bees and wasps, there is a distinct male, 

 and in one family the female is wingless, the male winged (fig. 40). 

 Beetles display little external difference ; exceptionally the male bears 

 horns (fig. 56) ; in some wood-boring beetles the male is wingless (fig. 86). 



FIG. 56. 



Male Stag Beetle. 



Butterflies display great sexual differences in colour, form, etc. ; we repro- 

 duce one species (figs. 58-59) in which they are very strikingly different. 

 Moths rarely display great or noticeable differences, more often small 



