H74 On Aquatic Oarnivorous Coleoptera or Dijtiscidie. 



having to sink in consequence of its prior use by Crotcli. Hydroporus sibiiicus Ls described by me under 

 the same uanio (No. r)8."5), and GaurodytPs nigripulpis is I believe the species I have characterized as 

 Agabus borealis (No. 707), iu this case, Dr. yaiilberg's name lias the ])riority. The rest of the Scandina- 

 vian describer's new species are unknown to ine. He also treats Hydroporus nigritarsis (No. 543), as a 

 variety of H. bilineatus, which, as already suggested by me, is iirobaldy correct. 



In mv remarks on Hydroporini (p. 928), I have stated that in this aggregate it is only iu the 

 genus Hydroporus that the iutercoxal process of the metasternum conuects with the mesosterual fork. I 

 have, however, found by dissection of Hyphydrus decoratus (No. ."iHS), that the connexion in cpiestion 

 also exists in this sj)ecies, which mu.st therefore be separated from the CujlambL The contact is however 

 of the most minute and imperfect character, and w-ould not justify (even if other characters were left out 

 of consideration) the location of the species in Hydroporus. As there are several American si)ecies I 

 have not been able to examme, that may possibly present an approximate structure, I shall not formally 

 propose a new generic name for this insect till more thorough investigation has been made. 



Dr. Horn has just published in the Trans. Am. Ent. Soc, July, 1881, pp. 91 to 196, an important 

 paper on the genera of Carabidie, iu which he moreover discusses the classilication of the families of Carni- 

 vorous Coleoptera. 1 am very glad to find that he is in accord with the views I have expressed here and 

 previously (iu Compt. rend. Soc. Belg., XXIII, p. cxlvii.), as to the removal of the Haliplini and 

 Pelobius from the Dytiscidse. The talented American entomologist does not, however, agree with me 

 as to locating Amphizoa in the Dytiscidw, and he has made known to us a striking observation that has 

 an important bearing on this point, viz., that in the wonderful Carabideous genus Mormolyce the iuter- 

 metliate coxal cavities are formed as they are in the series Dytisci comjjlicati. When I exposed (ante, 

 p. 846, et seq.), my reasons for placing Amphizoa at the head of the series just named, I concludetl 

 with saying, " as there are no Carabidie having the middle coxal cavities formed as tliey are in 

 Amphizoa;" Dr. Horn's unexpected discovery has rendered this premiss incorrect, and greatly invalidated 

 the most important of the facts to which I appealed, and 1 think therefore at present it would be better 

 to remove Amphizoa from the Dytiscidre, and treat it in the same manner as Pelobius. I do not agree 

 however with the elevation of these isolated inteiinediate forms into families equivalent with such a vast 

 complex as the Carabidw, l>ut as I am about to dilate on this elsewhere, it is here only necessary for m<i 

 to make known the modification of my views that Dr. Horn's discovery has necessitated. 



