classification of the Adephacia. 69 



vide Hydroporides) five-jointed tarsi, yet so also do a vast 

 number of other Coleoptera not included in the Adephaga ; 

 and we cannot therefore take this into consideration, 

 more especially when we recollect that the tarsi of 

 Gyrinid(e are absolutely unique in their structure. 4th. 

 The abdominal structure : in immediate sequence to the 

 paragraph I. have last quoted from Dr. Horn, there 

 follows in his memoir another, in which he demonstrates 

 that the ventral structure in Gyrinidce is different from 

 what prevails in the other families, and in point of fact 

 it is undoubtedly the case that the Gyrinidce have six 

 ventral plates stretching quite across the under surface, 

 and a seventh plate visible only on each side, while the 

 true members of the adephagous series have five ventral 

 plates extending all across the body, and a sixth visible 

 only on each side. Thus in this character, as in all the 

 others I have discussed, the GyrinidcB depart from the 

 other members of the adephagous series ; and it is 

 perfectly clear that the Gyrinida. are not connected with 

 any of the other components of the series by any 

 characters of such immediate importance as connect 

 these other components inta- se. 1 think the Gyrinida. 

 will prove one of the most isolated of all the families of 

 Coleoptera, and it is therefore not advisable to place them 

 in a series, all of whose other components are linked 

 together in the most intimate relations. I do not intend 

 by this to deny that the Gyrinidce may find their nearest 

 allies in the Adephaga, ; that is quite another question 

 from the above. 



I must not pass from the consideration of Dr. Horn's 

 paper without making some apology for the rather 

 critical nature of my remarks, but this is scarcely neces- 

 sary, for we all know that he is one of the most unpre- 

 judiced admirers of truth and accuracy, and I am con- 

 vinced that he will no more be likely to find fault with me 

 for discussing some of his conclusions than the lamented 

 Chaudoir would have been to disagree with him because 

 of his criticisms ; but I cannot conclude without point- 

 ing out that, although we are still far from possessing a 

 perfect classification of the carnivorous Coleoptera, yet 

 Dr. Horn's paper shows that we are on the right road 

 for getting one ; and his contribution will undoubtedly 

 prove to be a considerable assistance to those who, like 

 himself, will have the courage and perseverance to aid 

 research in this direction. Such a large amount of 



