974 On Aquatic Carmwvorous Coleoptera or Dytiscide. 
having to sink in consequence of its prior use by Crotch. _Hydroporus sibiricus is described by me under 
the same name (No. 583), and Gaurodytes nigripalpis is I believe the species I have characterized as 
Agabus borealis (No. 707), in this case, Dr. Sanlberg’s name has the priority. The rest of the Scandina- 
vian describer’s new species are unknown to me. He also treats Hydroporus nigritarsis (No. 543), as a 
variety of H. bilineatus, which, as already suggested by me, is probably correct. 
In my remarks on Hydroporini (p. 928), I have stated that in this aggregate it is only in the 
genus Hydroporus that the intercoxal process of the metasternum connects with the mesosternal fork. I 
have, however, found by dissection of Hyphydrus decoratus (No. 388), that the connexion in question 
also exists in this species, which must therefore be separated from the Celambi. The contact is however 
of the most minute and imperfect character, and would not justify (even if other characters were left out 
of consideration) the location of the species in Hydroporus. As there are several American species [ 
haye not been able to examine, that may possibly present an approximate structure, I shali 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 Carabidze, in which he mereover discusses the classification of the families of Carni- 
vorous Coleoptera. J am very glad to find that he is in accord with the views I have expressed here and 
previously (in Compt. rend. Soc. Belg., XXIII, p. cxlvii.), as to the removal of the Haliplini and 
Pelobius from the Dytiscide, The talented American entomologist does not, however, agree with me 
as to locating Amphizoa in the Dytiscid, 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 inter- 
mediate coxal cavities are formed as they are in the series Dytisci complicati. When I exposed (ante, 
p. 846, et seg.), my reasons for placing Amphizoa at the head of the series just named, I concluded 
with saying, ‘“‘as there are no Carabide having the middle coxal cavities formed as they 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 I think therefore at present it would be better 
to remove Amphizoa from the Dytiscide, and treat it in the same manner as Pelobius. I do not agree 
however with the elevation of these isolated intermediate forms into families equivalent with such a vast 
complex as the Carabidz, but as | am about to dilate on this elsewhere, it is here oniy necessary for me 
to make known the modification of my views that Dr. Horn’s discovery has necessitated. 
