2 BEITISH APHIDES. 



purposes ; otlierwise to our minds order would revert 

 to chaos. 



Much has yet to be done in comparing and collect- 

 ting Aphides from other countries, so that there is a 

 probability that species will yet be discovered to enrich 

 genera, as yet but poorly represented. The science of 

 embryology is daily contributing to a sound phylogeny, 

 which really lies at the root of all natural systems. 



The Aphididee seem to extend over all the regions 

 of the Northern Hemisphere, extending from the 

 extreme west of Asia, throughout Europe, and across 

 the entire continent of North America. Species have 

 been taken, but not as yet identified, on the slopes of 

 the Himalaya, and probably it only wants attention to 

 show that they obtain also in the temperate regions 

 of Africa. 



The great problem of the day, and likely to be for 

 many years hence, is the possible development of higher 

 out of lower forms. Kant says " Geologists are archaeo- 

 logists of nature, and the sole irrefragable and direct 

 evidence of the method by which living things have 

 been what they are is to be sought amongst fossil 

 remains." 



The great difiiculty that the Entomologist feels in an 

 appeal to the rocks for evidence, is the comparative 

 scantiness of specimens hitherto brought to observa- 

 tion, and the bare indications yielded as to the sequence 

 of insect orders in the world's history. The fragility 

 of the bodies of many insects is doubtless one cause of 

 this imperfection of the record; but, as the ancient 

 Devonian beds give unmistakable indications of their 

 occurrence, this branch of the animal kingdom must 

 have come into existence at a very early stage of time. 



The rise of insect life on our globe has been well 

 treated by several competent writers. The attempt 

 to introduce so large a subject into this Monograph 

 would be quite out of place, but briefly it may be 

 noted that an examination of the most ancient fossils 

 yet discovered, shows that insects, even at the above 



