The Insect Fauna of Tan Diemen^s Land. 301 



he considered the disproportion between the Fauna and the 

 Flora to be the great characteristic difference between these 

 islands and the first-mentioned division of Australasia. 



The character of organised nature on the continent of 

 New Holland and its dependent islands^, of which Van 

 Diemen's Land is the most important^ is more peculiar than 

 that of any other part of the world. Notwithstanding 

 some peculiarities^ New Zealand appears in general closely 

 connected with New Holland. 



The character of an insect Fauna is much influenced by 

 that of the corresponding Flora, even if, as in the present 

 case, the former does not entirely depend on the latter. 

 Unfortunately we are not yet able to trace the influence 

 the Flora exercises on the insect Fauna: to do so we 

 require to have a knowledge of every plant which affords 

 nourishment to each species of insect, both in its first and 

 last stage. Of this knowledge we are now wholly deficient, 

 and yet it is of the greatest importance in our study of 

 the geographical distribution of insects, for by it alone 

 can we determine the connection between Flora and Fauna. 

 For example, were the numerous species of the genus 

 Taropsis (Blatthafer) to be found only on one family or 

 genus of plants in New Holland, the knowledge of the 

 limits of this family or genus would have a double signi^. 

 fication. We must hope for future elucidations of the 

 intimate connection between the Fauna and Flora, and 

 confine ourselves now to a comparison of their more distant 

 relations, — a comparison from which interesting results are 

 nevertheless obtained. In the vegetation of New Holland, 

 the most important families, such as J^olypodiacece, Graminea', 

 CyperacecE, OrcJddacecB, Compositce, Eiipliorhlacece, and Fapi- 

 lionacece, have an equal distribution, and are in the same 

 proportion to the rest of the Flora as in other countries. 



