MR. A. MURRAY'S MONOGRAPH OF THE FAMILY OF NITIDULARLE. 225 
than any other genus of the Nitidularie. I know of no instance in the zoological world 
where very great differences in size exist in the same family. We should hesitate to class 
a mouse with an elephant even although it were to possess a trunk and tusks. Some 
thirty or forty years ago the Foraminifera were classed with the Nautili, but it is 
long since the totally different nature of the two objects has been recognized. In like 
manner (although in a less degree) I think the difference in size too great to allow us 
readily to class Cybocephalus with the Nitidularie. Further, Cybocephalus has a pecu- 
liarity in habit not possessed by any of the true Nitidularie. Its body is so constructed 
that it can roll itself up into a ball. 
Next, as regards the Peltide and Trogositide, of which I prefer to speak first, as dis- 
playing the greater amount of divergence, before discussing the Rhizophagi, which form 
the transition between the Nitidularie and them, it is to be noticed that, while undoubt- 
edly nearly allied to the Nitidularie, they differ in two very important points: they have 
two lobes to the maxille, a character found in most of the families of Clavicorns which 
naturally follow them ; they have also the first article of the tarsi smallest, instead of the 
fourth. The Trogositide, moreover, have a distinct facies and are considerably larger 
in size; and although the Peltide preserve a greater resemblance to the Nitidularia, 
they possess similar tarsi and maxille to the Z7'rrogositide, and the species naturally 
arrange themselves with them. If we hold that the 700084110 form a distinct family, 
the Peltide must go with them. 
The disposal of the genus Rhizophagus is a matter of greater difficulty. It forms the 
passage between the 12106 and Trogositide. Ips is the last group of the Nitidularie. 
It is well marked by the epistome projecting over the mandibles, but in other respects 
it does not differ from the rest of the family. It has only one lobe to the maxill:e; it 
has Nitidularian tarsi, viz. dilated, with five articles, of which the fourth is smallest. 
Fig. 17 shows the tarsus of Ips. Rhizophagus, on the other hand, has the tarsi five- 
jointed in only one of the sexes. In the Fig. 17. Fig. 18. 
males there are only four articles, and the 
tarsi are less dilated than is usually the case = 
in the Nitidularie. Fig. 18 shows the five- 
jointed tarsus of the female Rhizophagus. / 
Further, Rhizophagus has two lobes to the Tarsus of Ips 4-signata. EM 
maxille, whilst the rest of the Nitidularie 
with which it has closest affinities have only one. Contrast fig. 4 (the maxilla of Rhizo- 
phagus) with fig. 3 (the maxilla of Thalycra fervida), which may be taken as a fair example 
of the normal form of that structure in the JVitidularie. It may be said that its 
possessing two lobes is no reason for removing it from them, because the Brachypteride, 
` a group of Nitidularie at the other end of the line, have two also. This is true; but 
use of extremely high magnifying powers ; I have examined the tarsi placed in essences ; in fine, I have disarticulated 
them between two plates of glass, and I have remained convinced that no article existed, as I have said, at the base of 
thelatter. Care must be taken in this examination not to allow one's self to be imposed upon either by the cavity of 
the third article, in which the fourth is implanted, or by the feeble basal swelling of the articulation of the latter. 
Erichson was probably deceived by some such illusion." (Duval, Genera des Col. d'Eur. ii. p. 151.) 
