26 On an anomalous genus 



sources of this gentleman, and his great acquirements as a 

 naturalist, cannot fail to render this intended publication 

 equally interesting and valuable. 



. I am, Dear Sir, 



Yours very truly, 

 Ryder St. Dec. 20, 1837. Wm. Yarrell. 



Editor of Mag. Nat. Hist. 



Art. V. On Coptosoma, an anomalous genus of Heteropterous In- 

 sects. By J. O. Westwood, Esq. F.L.S. &c. 



The illustrious Swammerdam, long ago, remarked upon the 

 great advantages to be derived from thoroughly investigat- 

 ing a single species, belonging to each of the great types 

 of the insect tribes ; whereby the student would be enabled 

 to obtain a knowledge of the general structure of the entire 

 class. No advice could be more philosophical, for no me- 

 thod could be devised, by whieh we can so completely master 

 the difficulties attending the investigation of such an im- 

 mense series of minute creatures. To know, for instance, that 

 having made ourselves well acquainted with the cockchaffer, 

 in all its peculiarities of organization, we have learned the 

 general formation, in all probability of nearly 100,000 distinct 

 species of Coleopterous insects, is in itself a sufficient ground 

 for adopting Swammerdam's advice ; but there is still another 

 reason, which scarcely yields to the former, namely, that by 

 instituting a comparative examination of the structure of any 

 particular organ, throughout each of these chosen types, in 

 conjunction with its varied uses, we are enabled to obtain 

 more perfect physiological views of these tribes, than could 

 possibly be obtained by studying any single species, in the 

 utmost detail. We are in this manner more completely able 

 to trace those modifications and apparent anomalies of struc- 

 ture, which so constantly meet us in our researches, to their 

 true source, and to ascertain wherefore they have been given 

 to the species. For example, having carefully studied a com- 

 mon white garden butterfly, and ascertained that its spiral 

 tongue is composed of two distinct pieces, representing, in 

 their situation, the maxilla of beetles, and applicable for col- 

 lecting the nectar of flowers, we at once, and in the most 

 satisfactory manner, come to the conclusion, that the very 

 elongated filaments which proceed from the mouth of the Co- 

 leopterous genus Nemognatha, are the real maxilla of the 

 beetle, notwithstanding their very attenuated form, and that 

 their use must be analogous to that of the spiral tongue of the 

 butterfly. 



