( Ixxxv ) 



Lichens (1872) . . . 6,250 



Alg83 (1889) . . . 22,478 



Fungi (1889) . . . 35,311 



78,416 



178,636 



And having regard to the dates at which these estimates 

 have been made by various authors, he expresses his con- 

 viction that the good species described and recognised by 

 authors well acquainted with the subject up to the present 

 time are over 300,000, as against from 200,000 to 250,000 

 insects. 



It must be remembered that Botany is a much older and 

 more advanced study than Entomology ; the vegetable pro- 

 ductions of the earth are at this moment far better known, 

 worked out, and systematised than are the insects, and there- 

 fore the proportionate amount of labour involved in classifying 

 and incorporating into any collection a given number of 

 botanical specimens (except, perhaps, in the case of the more 

 obscure cryptogams) is less than would be involved in dealing 

 with the same number of insects, of which a far larger per- 

 centage would certainly be new and undescribed. 



This point can, I think, be very fairly illustrated by 

 observing the comparative numbers of plants and insects 

 dealt with in the ' Biologia Centrali-Americana,' to which I 

 have already referred. In that publication, dealing, as I 

 have said, with an area of less than 100,000 square miles, the 

 number of plants enumerated are 12,233, of which 607, or 

 rather less than 2^ per cent., are cryptogams ; but in this 

 enumeration algae, lichens, and fungi are excluded. If we 

 take the proportion of these on the basis of Mr. Carruthers' 

 figures, we should add 21 per cent., or roughly 2565, for these 

 groups, by which we arrive at an estimate of about 14,800 

 known species in the Botany of that region, of which about 

 440 are new, as against over 30,000 species of insects, of 

 which some 14,000 will probably be found to be new when all 

 are worked out. I think it would be safe to conclude that 

 each plant throughout the world nourishes on an average at 

 least two distinct species of insects, although, of course, 



