502 HYMENOPTERA 



at present is to bring to the eye of the reader the great diversity 

 of outer form that is believed, rightly or wrongly, to result from 

 the mode of treatment of the young. And we will also take this 

 opportunity of more fully illustrating the remark we made on 

 p. 85 as to the profound distinctions that exist between ants 

 and white ants, or Termites, notwithstanding the remarkable 

 analogies that we shall find to exist in many of their social 

 arrangements. 



The analogies we allude to, coupled with the fact that there 

 is a certain general resemblance in outer form between the 

 workers of Termites and ants, and even between the extra- 

 ordinary castes called soldiers in the two groups, have given rise 

 to the idea that there is a zoological relationship between the 

 social forms of JSTeuroptera and Hymenoptera. The two are, 

 however, zoologically amongst the most different of Insects. 

 The external skeleton in Termites is remarkable for its im- 

 perfect development, the sclerites being small and isolated, while 

 the segmental differentiation of the body is low (Fig. 225, etc.), 

 so that there is no difficulty in counting the segments. In ants 

 the reverse is the case as regards both these facts, the various 

 segments being most unequal, so that their homologies have only 

 been detected after prolonged studies, while the chitinisation and 

 articulation of the various parts is so complete that the ant may 

 be described as cased in armour, fitting together so exactly that 

 it is difficult anywhere to introduce the point of a needle into 

 its chinks. The wings of the two kinds of Insects are also 

 extremely different. The differences between the modes of 

 growth and development of the two sets of Insects are as pro- 

 found as the distinctions in their anatomy. Termitidae belong 

 to the division of Insects in which the wings are developed 

 outside the body ; Hymenoptera to the division in which they 

 are developed inside the body. In Termites the growth of 

 the individual is slow, and the final form is reached gradually. 

 In the ants the growth is carried on with great rapidity, and 

 during it the Insect is a helpless maggot absolutely dependent 

 on the attentions of its seniors, while the difference in form and 

 structure between the ant -larva and the ant are enormous. 

 Both anatomy and ontogeny are profoundly different in ants 

 and Termites. To these distinctions must be added, as of much 

 importance, the fact that in Hymenoptera only the female sex 



