specific differences in the Saws of 2 Dolerids. 483 
show numerous denticulations, large and conspicuous in 
triplicatus and madidus, less so in the other species. Tincti- 
pennis (Plate XXIV, 4), though an entirely black insect, 
has a saw presenting so distinctly the characteristics of a 
Dosytheus, that, until I myself dissected a British specimen 
and found the saw here figured, I had always a suspicion 
that Cameron had made some mistake, and that the saw 
mounted by him in balsam (now in the 8. Kensington 
Coll.) and figured in his Monograph, did not really belong 
to the insect to which he assigned it! No other black- 
bodied Dolerus has a saw in the least resembling it, and 
I can only group it (in spite of the insect’s external char- 
acters) with those of pratensis, aericeps, etc. 
We come now to a large group of species (Plates 
XXIV, 6 to XXV, 4 inclusive) whose saws are easily 
distinguished from any of those hitherto considered, but 
as a rule not at all easily distinguished from one 
another. The diagonal corrugations of the blade seem 
to be always quite simple—merely a series of alternate 
straight and equal ridges and furrows. The so-called 
teeth are always distinctly projecting, triangular (not 
quadrate) in outline and separated from each other by 
rather wide but not very deep sinuations or emargina- 
tions; those nearest the apex of the saw are hardly 
denticulated at all, but towards its centre a few dis- 
tinct denticulations begin to appear, and still nearer the 
base they are often pretty numerous, but always very 
small and visible only with high magnifications. (Unfor- 
tunately, as already explained, I have been unable to 
include this part of the saws in my figures.) The superior 
margin of the saw is always simple, not lumpy at the apex ; 
and it generally coincides with the long linear groove, etc. 
which connects together the saw and its “support.” In 
some of my figures (e.g. Plate XXIV, 6 and 7) the 
presence of denticulations on the cutting edges of the 
organ can be detected without much difficulty, but in 
others I can only see them with the help of a magnifying 
glass, and in some I have not succeeded in making them 
visible at all. The general appearance of all these saws 
is pretty much the same; none of them are particularly 
wide or narrow or in any other way paradoxical. A few, 
however, by dint of considerable experience I can recog- 
nise at axglance—e. g. Plate XXIV, 11, 12 by their curved 
“faleate ” shape, the superior margin distinctly sinuated 
