298 



of the head. In the Aiichenorhynchi, the head is ahvays moie 

 or less declivous and 'bent under; and at, or near, the angulation 

 or midst of the rounding, there is almost always a transverse 

 keel, or false suture ; or on either side of an imaginary Hue, the 

 (juality of the sculpturing is dififerent, so that as a rule it is 

 practicable to consider that there are 2 nameable and distin- 

 guishable areas, which are called 'fcrtcx' and 'froiis', not, how- 

 ever, strictly homologous to the 'vertex' and 'frons' in other or- 

 ders, though, like them, strictly terms of convenience and not 

 designations of separate sclerites ; that they really are onf^ '^'^1'^- 

 rite may, apart from embryological evidence, be inferred from 

 the position of the ocelli, — in many Tetigonioidea the 2 ocelli are 

 close to the base of the vertex — while in some Fulgoroidea, two 

 are on the genae, an extra ocellus being ]:)resent right on the 

 apical margin of the frons. 



It follows, therefore, that the vertex may be ]mrtly ventral, or 

 contrariwise the frons may be partly dorsal. The first con- 

 tingency occurs among the Agalliinae, where the ocelli are often 

 found far on the ventral aspect of the head ; the latter occurs in 

 certain Fulgoroidea, in whith the vertex is very short, (in many 

 Fulgoroids in which the vertex and frons are confused, I suspect 

 that the former is entirely absent, as in some, it is represented 

 merely by a linear section,) and apparently also in some Cerco- 

 pids. Van Duzee uses thp term "face"' to designate the ven- 

 tral aspect of the head, including the ventral part of vertex, the 

 frons, genae, etc. vStal occasionally seems to follow the prac- 

 tice of workers in other orders, but this author rarely explained 

 his horismology and is frequently ver}' obscure. Edwards dis- 

 tinguishes a 'forehead' between the crown (vertex) and face. 



The frons is rarely anastomosed with the clypetts. Sometimes 

 it is so, discally, being sometimes then sutured ofi laterally. 



The genae are the lateral parts of the head, sometimes placed 

 actually laterally (Fulgoroidea) or ventrolaterally (Tetigonioidea), 

 and are usually separated from the frons and vertex by keels or 

 false .sutures. Owing to the peculiar structure of the head in 

 the Fulgoroidea the tempora do not seem to be separable ; in the 

 Tetigonioidea they are usually seen as narrow strips extending 

 from the antennal scrobes to the posterior margin of the front, 

 sometimes onto the lateral parts of the vertex ; they are very 

 conspicuous in Tarfessiis. The lorae are two small plates usually 

 more or less crescentiform, lying between the clypeus and the 

 genae, separable from them by false sutures and present only iit 

 the Tetigonioidea; they correspond with the juga in certain He- 



