PROOFS, ILLUSTRATIONS, AUTHORITIES, ETC. xvii 



and the Agrionidae, as a few Termites and a long series of beaked 

 insects. 



" This is the case also in the succeeding period, that of the Chalk, 

 in which neither Butterflies, nor Bees, nor Hymenoptera generally, 

 have been found. The Beetles, on the other hand, occur in somewhat 

 larger proportion. 



" In this cretaceous period there existed islands rising from the 

 sea and chiefly wooded with fir-trees, bearing also Palms, Dragon- 

 trees, and tree-like Lilies, together with which the first dicotyledo- 

 nous trees occur. These, however, appear to have been as yet very 

 few in number, it being only in the following period, the tertiary, 

 that they became plentiful, forming from this time an essential pro- 

 portion of the vegetable kingdom. In company with the creation of 

 dicotyledonous trees and phanerogamic herbs, the Insect- world appears 

 to have been first developed at this period in all its orders and in 

 more manifold forms. Whilst at present we are acquainted with 

 only 126 species of insects altogether, from the earlier geological 

 periods ; from the two tertiary localities of (Eningen and Radoboj I 

 know of about 443 species. Among these are present all the seven 

 orders of recent insects, but, nevertheless, in different numerical pro- 

 portions to those of the existing faunae. In these the Ametabola 

 form about 0*10, the Metabola 0'90 [as to individual specimens]. 

 Of the (Eningen and Radoboj species, 124 belong to the .Metabola, 

 and 319 to the Ametabola, the former making more than a third. 

 We see, therefore, that at this period the Ametabola were much more 

 numerous in proportion than the Metabola, although not more in the 

 mass, as in former geological periods." Heer on the History of 

 Insects, Leonkard and Bronris Jahrb. f. Miner, u. s. w. 1850. 

 Translated in Q. J. Geol. Soc., Nov. 1850. 



Professor Heer intimates a connexion between the creation of the 

 various kinds of insects and the rise of conditions fit for their ex- 

 istence. With regard to the scarcity of insects in the early times, 

 he says " Nor need we wonder, if we consider that at present also 

 our Lycopodia and Equiseta harbour no insects, and the Filices very 

 few. The hosts of insects, therefore, that live on the flowers and 

 their honey, on the fruits and seeds, could not at that time have been 

 in existence, the vegetable world being then destitute of flowers and 

 fruits." 



The Bees and Butterflies appear in the tertiary, in very few forms. 

 " In the existing creation only," he says, " have these insect types 

 been developed in their full richness of form and splendour of colour ; 

 and this may be the better understood, inasmuch as in the tertiary 

 period the land was almost entirely occupied with woody plants and 

 forests, and offered but few herbaceous flowering plants from which 

 the Butterflies and Bees could derive their nourishment." 



" Among the Metabola we first meet with the flies." " The Ne- 

 mocera were the first to appear, and were followed a little later by 

 the Brachocera" the other and greater division of Diptera. Heer 

 remarks that the Nemocera might be the first to appear, because of 



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