EXTERNAL ANATOMY OF INSECTS. 487 



where that part exists, by the occiput. The vertex may 

 be denominated the ordinary region of the stemmata : 

 for though in several cases, as we have just seen, one or 

 more of them are planted in the front; yet this in the great 

 majority, especially in the Hymenoptera, is their natural 

 station. In Blatta and some other Orthoptera the poste- 

 rior angle of the head is the vertex. In many dung- 

 chafers of Latreille's genus Onthophagus, which are said 

 to have occipital horns, as O. nutans, nuchicornis, Xi- 

 phias, &c, the horn really arms the part I regard as the 

 vertex. In Locusta Leach, this part is very ample, and 

 in Truxalis very long ; but more generally it is small, 

 and not requiring particular notice. 



v. Occiput*. — The occiput, or hind-head, is that part 

 of the face that either forms an angle with the vertex 

 posteriorly, or slopes downwards from it. ' It has for its 

 lateral boundaries the temples, and behind it is either 

 terminated by the orifice of the head, or in many cases 

 by the neck. In those beetles that have no neck, as the 

 Lamellicorn and Capricorn, the hind-head is merely a de- 

 clivity from the vertex, usually concealed by the shield of 

 the thorax, very lubricous, to facilitate its motion in the 

 cavity of that part, and at its posterior margin distin- 

 guished by one or two notches, which I shall notice 

 hereafter, for the attachment of the levator muscles : but 

 in those beetles or other insects that have a neck, or a 

 versatile head, the occiput forms an angle with the vertex, 

 often rounded, and sometimes acute. This structure may 

 be seen in Latreille's Trachelides, and several other bee- 

 tles. In the Hymenoptera, Diptera, and others with a 



« Plates VI. VII. e. 



