560 EXTERNAL ANATOMY OF INSECTS. 
Mantis in a similar situation; but I cannot trace it in 
Locusta, or in the other Orders. 
Having considered the parts that constitute the meso- 
thorax, we will next say something upon those, as far as 
they require notice, that compose the medipectus or mid- 
breast. But first I must observe in general of the me- 
dipectus and postpectus taken together, or the whole un- 
derside of the alztrunk, that though usually they are in 
the same level with the antepectus or under side of the 
manitrunk, yet in several instances, as the Scarabaida, 
the Staphylinide, &c. they are much more elevated than 
that part; they are also usually longer, very remarkably 
so in Atractocerus, but in Elater sulcatus and many others 
they are shorter. These parts are also commonly rather 
more elevated than the abdomen,—much so in some, as 
Molorchus ; but scarcely at all in others, as Buprestis, 
the Heteropterous Hemiptera, &c. In some of the latter 
(Scutellera) the abdomen seems the most prominent. 
Another observation relating to this part must not be 
omitted, namely, that though in many cases the medipec- 
tus and postpectus are perfectly distinct and may be se- 
parated, yet in others, as for instance the Lamellicorn 
beetles, the Hymenoptera and Diptera, &c., no suture 
separates them ; so that though the upper parts, the me- 
sothorax and metathorax, are separable, the lower ones 
just named are not so. 
6. Peristethium?. ‘The first piece of the medipectus is 
what I have called, after Knoch, the peristethium”. This 
a Prates VIIE. IX. x’. 
> At first I had named this piece the antecosta, and the mesoste- 
ihium the postcosta ; and there is certainly some analogy between the 
