lir PROCEEDINGS OF THE 



available data for investigating the history of species and their 

 genealogy, their origin, progress, migrations, mutual relations, their 

 struggles, decay, and final extinction. It is to be feared that in in- 

 sects, as in plants, but too large a proportion of the innumerable 

 genera and subgenera have been founded rather on the sortings of a 

 collector than on the investigation of affinities ; and, indeed, that 

 must in a great measure be the case so long as a large number 

 are only known from their outv^ard form at one period only of their 

 varied phases of existence. 



The days of a ' Systema Naturae ' or single work containing a 

 synopsis of the genera and species of organized beings are long since 

 passed away. Even a ' Species Plantarum,' now that their number at 

 the lowest estimate exceeds 100,000, has become almost hopeless. 

 The last attempt, De Candolle's ' Prodromus,' has been nearly forty 

 years in progress ; the first portion has become quite out of date ; and 

 all we can hope for is that it may be shortly completed for one of 

 the three great classes. Animals might have been more manageable, 

 were it not for the insects. Mammalia estimated at between 2000 

 and 3000 living species, Birds at about 10,000, Reptiles and Am- 

 phibia under 2000, Fishes at about 10,000, Crustacea and Arachnida 

 rather above 10,000, Malacozoa about 20,000,yermes, Actinozoa, and 

 Amorphozoa under 6000, would each by themselves not impose too 

 heavy a tax on the naturalist experienced in that special branch 

 who should undertake a scientific classification and diagnoses of all 

 known species ; and in one important branch, the Fishes, this work 

 has been most satisfactorily carried out in Dr. Giinther's admirable 

 genera and species of all known Fishes, published under the mislead- 

 ing title of ' Catalogue of the Fishes in the British Museum,' and 

 recently completed by the issue of the eighth volume. The sound 

 philosophical views expressed in his preface to that volume (which, 

 by some strange inversion, bears a signature not his own) can be 

 appreciated by us all ; and zoologists are all agreed as to the care 

 with which they have been worked out in the details. Insects are, 

 however, the great stumbling-block of zoologists ; the number of 

 described species is estimated by Gerstacker at about 160,000, 

 viz. Coleoptera 90,000, Hymenoptera 25,000, Diptera 24,000, Le- 

 pidoptera 22,000-24,000. Mr, Bates thinks that, for the Coleoptera 

 at least, this estimate is too high by one -third ; but even with that 

 deduction the number would exceed that of plants, and it is probable 

 that the number of as yet undiscovered species in proportion to that 

 of the described ones is far greater in the case of insects than in 

 plants. We can therefore no longer hope for a ' Genera and Species ' 



