258 THE CAUSES WHICH 



life on these centres, and apply these in accounting for the 

 progressional aspect of extinct life on the same and other areas. 

 In this way it is proposed by the co-operation of zoologists and 

 geologists to localise the various genera of life on the earth^s 

 surface ; trace these to some original general dissemination, like 

 that of the elephants which in Tertiary time roamed the old 

 world from Northern Europe to Australia, or to some original 

 centre of distribution; and to consider how far their tendency 

 to variation will allow of their being allotted a single typical 

 ancestor, then or there originating. 



In regard to our present topic, Entomology, these theories 

 have been worked on by students with more or less success ; but 

 as they are all dependent on the geological evidence of an anti- 

 quity and progression of species, for which they seek to afford a 

 reason, it will be well to examine how we come to obtain a 

 history of a past succession of insect races on the terrestrial 

 surface, and give some idea of the extent to which this record 

 has been deciphered. To attain this end it will be necessary to 

 divest our mind of any bias to the notion that these familiar 

 woods and w^ell-known hedgerows, along which we stray of a 

 summer's day to catch Fritillary and Hair Streak Butterflies, 

 are more substantial than the transient and highly- coloured 

 images of dreamland. There was a time when they physically 

 were not, and a time may arrive when they shall not be. On 

 their drapery are inscribed thick the imjjerfect characters of 

 ceaseless change; periodically confessed in the burning green 

 of soft spring, or crisp and gold ink of sapless autumnal suns. 

 From the bosom of the maternal soil and darkness they shed 

 their odours and arise at the first whispers of the northing 

 beams, speed eddying in their solar life circles, fade and dissolve, 

 and then stand slumbering and mouldering on the chilled globe, 

 until again called to exuberance by the glowing atmosphere. 

 And so likewise in regard to the light, fairy, and elfin life that 

 sports in their tangles. On an ii'on globe, composed of hard and 

 sterile minerals, where atoms are thought to combine by affinity, 

 or attract and repel each other, where annihilation is not recog- 

 nisable, and nothing is virtually lost, breathing life, atmosj^heri- 

 cally pent in its varied sphere, clothes by incessant assimilation 

 its beautiful forms with the scant organic mould ushered in by 



