^10 FOURTH REPORT — 1884. 



in Germany, that we are indebted for the recent progress which 

 has been made in this department. Mr. Newport in our own 

 country has also lately entered upon this subject*. There can 

 be no doubt that our knowledge of the natural affinities of In- 

 sects will be idtimately much benefited by the laborious investi- 

 gations of such observ'ers, although there may not have been 

 acquired hitherto a sufficient number of facts to Avarrant any 

 extensive generalizations. Those of Leon-Dufour may be more 

 particularly alluded to as throwing some light on this subject. 

 This patient anatomist, in one of a series of the most elaborate 

 memoirs on the internal structure of the Coleopteraf, observes 

 that by dissecting insects he has been enabled to determine the 

 value of many purely entomological characters, to clear up doubts 

 with respect to the distinction of the sexes in certain cases, 

 and to add to the number of those characteristic marks which 

 had already been acquired from a study of the mouth, antennae, 

 and feet, and employed as the foundation of families and genera. 

 His researches have satisfied him that the system of LatreiUe is 

 for the most part in perfect harmony with anatomical facts. 



(3.) Since the science of entomology has become so extensively 

 cultivated, and the field which it embraces been found to be so 

 extremely large J, naturalists have given up all attempt at a com- 

 plete Species Insectornm. They have even in many cases found 

 it impracticable to obtain a correct knowledge of any particular 

 order, regard being paid to all the included species. Hence they 

 have generally confined their researches to the more subordinate 

 groups, or to the insects of particular countries : and it is to such 

 works that we must have recourse, in order to learn the present 

 state of our knowledge of the different orders which are com- 

 prised in this class. It is not my intention, indeed it is not 

 practicable on the present occasion, to do more than indicate in 

 a general manner a few of the most valuable of such works which 

 have appeared of late years. 



It is to the Count De Jean that we are indebted for the most 

 extensive work which has been published on the order of Coleo- 

 pteraf, although it has not extended as yet beyond the Cicinde- 

 lidoi and CarabidcB. In a separate publication he has undertaken, 

 conjointly with M. Boisduval, the illustration of such species as 

 are found in Europe ||. Several important monographs have, 



• Phii. Trans. 1832. t ^«n- des Sci. Nat. 1824, &c. 



J Messrs. Kirby and Spence have estimated the probable number o£ existing 

 species of Insects at not less than 400,000. See IiUrod. to Entom., vol. iv. 

 p. 477. See also^ some remarks on this subject by Mr. Westwood in Loudon's 

 Magazine of Natural History, vol. vi. p. 116. 



§ Species general des Colcopteres. Svo, Par., 1825, &c. 



II Iconog. et Hist. Nat. des Coleop., 1827, &c. 



