Insects. 1983 



sus, it certainly never makes use of it, at least not in this situation, as I have never 

 found any of them attached by it, either to one another or to extraneous substances, to 

 the latter indeed, in this instance they cannot, as the pond is in the peat moor, and 

 there is neither stone nor any other substance on which it could possibly fix itself; in 

 specimens which I have opened I have not succeeded in finding it, although I have 

 in every case observed the small foot, its essential instrument of locomotion. I have 

 never heard any good account of the food of this mollusk, and its manner of eating : 

 from my own observation it appears to protrude a retiform substance through which it 

 very probably takes in animalcule, or perhaps decaying animal or vegetable matter. 

 The Anodon is found in great abundance in this neighbourhood, as well in the Trent, 

 which at high tides is here salt water as in our ponds and drains. It furnishes a very 

 favourite repast for the herons, which evince great dexterity in opening the shell. It 

 attains a considerable size, some I have seen being five inches in length. — E. S. 

 Bottesford-on-Trent, Lincolnshire, March 16th, 1847. 



A word on long scries. — Allow me to enter my protest against the practice which 

 now obtains among our collectors of British Lepidoptera of keeping in their cabinets 

 unreasonably long series of every species. I admit that the old system of having only 

 four or five individuals of a species is not to be defended when such species is variable, 

 but on the other hand, the keeping of twenty specimens answers no scientific purpose 

 when the characters of a species are constant. It may be all very well for those who 

 have no other purpose than making a cabinet a series of pretty pictures, and the con- 

 trast presented by whole rows of species may be very gratifying to their feelings. But 

 besides the degradation thus inflicted on science, rare species are confined to the 

 possession of few persons until they have made up their " row,'' instead of being 

 diffused among and increasing the knowledge of many. I may add, without intend- 

 ing any self-laudation, that if I had kept the fashionably-long series of twelve or twen- 

 ty, thousands of specimens would now be in my cabinet instead of being diffused 

 through the kingdom, and the collections of my entomological brethren would be to a 

 like extent deficient, at least as far as I am concerned. When speaking to one of the 

 plus gentlemen lately on this subject and showing the folly of the system, the best an- 

 swer I could get was " that Mr. did it, and therefore it must be proper ; '' and 



this, I believe, is the best reply that the majority of its adherents could give. In fine, 

 " it is a great evil, which is increasing and ought to be diminished.'' — J. W. Douglas ; 

 19, Nelson Square, Peclcham, November 20th, 1847. 



On the Entomological Zones of the Pyrenees. — At the meeting of the Academie des 

 Sciences on the 10th of May, 1847, was read a paper on the above subject by 

 M. Leon Dufour. 



" Insects," says the author, " like plants, are amenable to certain meteorological 

 conditions which favour, modify, or altogether prevent their fixed residence in certain 

 determinate zones. I say fixed residence, in opposition to a temporary station— a va- 

 grant and transitory habitation like that of certain Hymenoptera, Diptera, and Le- 

 pidoptera, which, during their active aerial existence, are the free denizens of many 

 zones, of which they are never more than the nomadic inhabitants. 



" Insects possess a great advantage over plants in being endowed with a power of 

 locomotion, whereby they are enabled to extend their zone of residence; but as a re- 



