specific differences in the Saws of Q Dolerids. 431 
would be difficult, if not impossible, to say from the char- 
acters of its saw only to what species a given insect belongs, 
these characters will often suffice to show that at any rate 
it does not belong to some particular species. For instance 
specimens of fumosus, oblongus, etc. (Plate XXV), are often 
hardly distinguishable by external characters from one 
another, or from other members of the same group, or finally 
from ngratus (Plate XXIV, 10). But on examining the 
saw of such a specimen we shall sometimes be able to say at 
once that at any rate it is NoT nigratus! Thus these saw- 
characters, even where they do not absolutely bring us to 
a conclusion as to the species of a particular insect, may 
at least supply us with a preliminary “ orientation ” of 
our ideas on the subject. And, as in the cases quoted 
above of gonager and puncticollis, sanguinicollis and ravus, 
they may be helpful towards forming an opinion as to the 
desirability or otherwise of uniting two doubtfully con- 
specific forms. 
I will now review shortly the saws here figured seriatim, 
pointing out such characters as I think noticeable in 
particular cases, and indicating the groups into which they 
appear to me most naturally to arrange themselves. 
Of the Loderus spp. (Plate XXIII, 1-4) I have already 
spoken. Palmatus and vestigialis are well-known and 
fairly common species. Pratorum I have figured from a 
specimen taken by myself at Woking. Guilvipes (= orna- 
tulus, Knw.) is from a specimen given to me by Konow as 
ornatulus. A fifth palaearctic form (genucinctus, Zadd.) is 
very rare, and I have been unable to procure a specimen. 
Passing to the species formerly distinguished as Dosytheus 
(Plates XXIIT, 5 to XXIV, 3), I think it is possible to 
recognise among them four or five fairly distinct groups. 
Etruscus and bimaculatus (Plate XXIII, 6 and 8) are 
evidently very closely allied by the quadrate form of the 
so-called saw-teeth,* and of the intervals or emarginations 
(almost as wide as themselves) which separate them. 
Pratensis, palustris and aericeps (Plate XXIII, 5, 7, 9) 
form a group which has much in common with etruscus and 
bimaculatus, but the saw-teeth (if I may call them so under 
* I should prefer to consider each of these so-called “ teeth” as 
a separate saw, and confine the term saw-teeth to those minute 
denticulations of their edges which can be clearly seen in my Figure 
of bimaculatus, but are hardly to be recognised except as a very 
slight sinuation in etruscus. 
