566 EXTERNAL ANATOMY OF INSECTS. 
its representative is a process of the latter part: yet as 
the peristethium and mesostethium are separated by no 
suture, though in some cases a transverse channel, and 
in others merely a coloured line, marks the point where 
they may be considered as soldered together, in these 
cases the mesosternum may perhaps be said to be 
common to both. In this great family, which includes 
within its limits some of the most singular and wonder- 
ful in their structure and armour, as well as some of 
the most brilliant and beautiful of the beetle tribes,— 
the part in question, in a vast number of cases, will en- 
able the Entomologist satisfactorily to trace its nume- 
rous groups, not only where it rises or stretches out into 
a horn or ridge, but even often where it is merely a flat 
space between the mid-legs. I shall notice some of its 
most striking variations in this tribe. In Phaneus fes- 
tivus, and in Macraspis and Chasmodia, itis elongated 
horizontally, with the apex curving upwards; in Ano- 
plognathus it is horizontal, straight, and figures an isos- 
celes triangle; in Gnathocera witticollis*, &e. it is very 
long, passing between the arms and nearly reaching the 
head; in Marmarina marmorea, Lanius, &e. it Is a lofty, 
robust, conical prominence; and in many Rutelida, 
especially those with striated elytra, it is pyramidal or 
four-sided ; it varies also in its termination, particularly 
in the Cetoniade; and even where there is little or no 
elevation of it, as in the Scarabaide MacLeay, it is often 
terminated anteriorly by lines that vary in their angle 
or curvature. The genus Copris, as restricted by Mr. 
W. S. MacLeay, may from an inspection of this cir- 
* Linn. Trans. xiv. 572. 
