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number of species of true insects of all orders existing on the 

 face of the globe. Dr. John Davy, in a letter to W. Spence, in 

 1853, estimates that 250,000 species of insects exist (Tr. Ent. 

 Soc. (n. s.), III., p. 32). The latest of these calculations is, 

 perhaps, that of my predecessor in this chair. At a meeting 

 of the Dumfriesshire and Galloway Natural History Society, 

 held at Dumfries in 1883, Dr. Sharp said : — " As the result of 

 a moderate estimate it appears probable that the number of 

 species of true insects existing at present on our globe is 

 somewhere between 500,000 and 1,000,000," and expressed 

 his own opinion, in which I entirely concur, that " the 

 number probably exceeds the higher of these figures, and will 

 come near to 2,000,000." Dr. Sharp has been good 

 enough to give me the approximate number of distinct 

 species of Coleoptera described up to the present time ; he 

 puts these at about 120,000, basing his calculation upon 

 the Munich Catalogue, published in 1868, which contained 

 77,000 species, and upon the additional descriptions since 

 published. 



Admitting that such calculations can be only approximate, 

 I have worked through the pages of the Zoological Eecord 

 with a view to arrive at the proportionate amount of descriptive 

 work done in each year in the different branches of Zoology. 

 I find that the average number of pages occupied in the Record 

 during the 24 years of its publication is 273 for Insecta, to 

 369 for all other branches of Zoology taken together, or, in 

 other words, that 42i per cent, of the record of all zoological 

 literature is occupied with insects against 57^ per cent, 

 devoted to other subjects ; Aves representing about 9i per 

 cent., Mollusca and Molluscoida 14^ per cent. Taking a 

 fairly average volume of the same publication, the volume for 

 1882, I find that the new species of insects described in that 

 year, deducting 8 per cent, for synonyms, amount to 5600, 

 whereas the wbole number of new species described in other 

 branches, with the same deduction, conies out at about 1650, 

 of which Mollusca are 772, Pisces 239, Crustacea 205, leaving 

 434 only for the whole remainder of terrestrial Zoology. This 

 in itself is sufficient evidence of what I may call the infancy 

 of our knowledge of the subject. 



