19:23] The Fulgorid^ of Eastern North America 141 



insensibly into the frons. Sometimes it rounds into the frons but is 

 more distinct. In still other cases it is sharply set off from the frons 

 and may be separated for its entire breadth from the frons by a more 

 or less distinct carin^e {Issina;, Megamclanus) or sulcus (Poblicia). 

 The vertex is sometimes prolonged along the dorsal side of the cephalic 

 process (Dictyophara, Scolops). Sometimes the vertex is furnished 

 with a more or less distinct median carina and another very common 

 condition is to have two lateral carinte converging towards the frons 

 (Cixiiis, many Delphacince). In this condition the vertex is divided 

 into three regions, the two lateral compartments between the lateral 

 carinas and the converging carina, and the central compartment pos- 

 terior to the converging carinse. Sometimes the central compartment 

 is divided by a median y-shaped carina into three compartments, the 

 frontal compartment and the posterior compartments. 



The frons is usually separated from the gensa by sharp carinse and 

 from the clypeus by a distinct sulcus. Its separation from the ver- 

 tex may be distinct and furnished by a carina or sulcus as mentioned 

 above or it may be impossible to distinguish the frons from the vertex, 

 in taxonomy the entire dorsal surface is usually called the vertex al- 

 though this may include a portion of what is the frons morphologic- 

 ally. The comparative length and breadth of the frons is often a 

 very useful character, as is its comparative width at the base, along 

 the vertex and at the apex, along the clypeus. 



The characters of the genas have not been much used but there are 

 frequently good generic characters present especially in the shape 

 and size of the antennal socket and antennal collar. 



The clypeus frequently furnishes reliable characters both in com- 

 parative size and shape and in the arrangement of the carinas. In the 

 subfamilies Fulgorince and DictyopharincF and some others the clyp- 

 eus is laterally sharply carinate but in other groups it is ecarinate 

 laterally. The depth of its insertion into the frons is also a useful 

 character at times. The clypeus frequently shades imperceptibly 

 into the labrum-epipharynx which may or may not be evidently di- 

 vided into its separate components. 



Ocelli are frequently present and usually these consist of a lateral 

 pair placed between the compound eyes and the lateral frontal 

 carina. In the CixiincB there is usually a very distinct frontal ocellus 

 at the apex of the frons. Sometimes this frontal ocellus is repre- 

 sented by a scar only. 



