THE FLY. 79 



for any " refuse " that may have dropped there since last tide. 

 We have now been down among the rocks for several hours, 

 and have collected enough material to supply us with interesting 

 work for several months, and learned such lessons out of Nature's 

 own book, as may afford us subjects of thought for a lifetime ; and 

 as we leave behind us the charming scenes of one of the happiest 

 days it has been our fortune to enjoy, we can only hope that every 

 member of the " Postal Microscopical Society " may be induced to 

 follow our example with the same beneficial results. 



By Fredk. Fitch, F.R.M.S., F.G.S., etc. 

 Plate 26. 



THE Fly belongs, strictly speaking, to the order Diptera, but 

 the word, as commonly employed, is incorrectly given to 

 many insects belonging to other orders. Thus, the May-fly 

 and Dragon-fly are of the order Neuroptera ; the Fire-fly and 

 Turnip-fly are, in fact, beetles, and of the order Coleoptera; 

 the Green-fly and Snowy-fly are Hemiptera; while the Oak Gall- 

 fly, Marble Gall-fly, Saw-fly, and Ruby-tail fly are, like bees, 

 belonging to Hymenoptera. But there are also the Onion-fly, 

 Carrot-fly, Cabbage-fly, Crane-fly, Hessian-fly, Bot-fly, Gad-fly, 

 Forest-fly, Drone-fly, Snout-fly, Blue-bottle fly, and Blow-fly, which 

 are all allied species, and come under the general term Diptera — 

 a word first employed by Aristotle twenty-two centuries ago, to 

 describe those insects which have two wings only. 



The order is an immense one. In species and individuals, it 

 far outnumbers any other order in creation. It is estimated that 

 there are 4,000 different genera, comprising 20,000 species. They 

 are besides very widely distributed, having been found in high 

 latitudes, where they are few and feeble ; in temperate climates, 

 where they abound ; and in tropical climates, where the most 



