( Ixxv ) 



It must, of course, be remembered that the description of 

 an insect does not necessarily involve any great amount of 

 labour; a fish, an echinoderm, or a sponge, may require 

 most careful preparation and dissection before its specific 

 characters can be fully recognised, whereas for the most part 

 the structural and superficial characters of insects are easily 

 distinguished and described, although the precise details of 

 neuration in Micro-Lepidoptera are not always easy to arrive 

 at, even by bleaching ; but what I desire to point out is the 

 immensity of the field of study, and the degree of ignorance 

 on the subject, which is evidenced by the vast number of 

 species hitherto unobserved which are annually recognised and 

 added to the general lists. The prevailing impression among 

 the uninitiated is that at least within the British Islands there 

 is nothing new to be discovered. A man who is known to pos- 

 sess a good collection of British insects is generally supposed 

 by his friends to have every species that can be found. It 

 would astonish the unentomological public to be told that a 

 Fellow of this Society recorded, in a single paper, in the ' En- 

 tomologist's Monthly Magazine ' for January, 1886, the occur- 

 rence of no less than 100 species of Diptera not hitherto 

 recognised in England, and Mr. Verrall informs me that he 

 would at this moment be able to describe at least a hundred 

 additional British species belonging to a single family, 

 showing that the study of Diptera, even as limited to the 

 British Islands, is by no means far advanced. 



The bulk of the record has been much increased during 

 the last ten years, and the proportionate number of pages for 

 general Zoology has been somewhat greater than in the pre- 

 ceding period ; this is chiefly to be attributed to the working 

 out of the ' Challenger ' collections, which, for obvious 

 reasons, were exceptionally rich in marine Zoology, and 

 deficient in insects. 



The Hessian Fly affords an excellent illustration of how a 

 minute insect, however common, may be overlooked for 

 many years ; for whether this species did, or did not, occur 

 in the days of the older economic entomologists, about which 

 much difference of opinion exists, it must, I think, be 

 admitted that its introduction cannot be dated within the 



