THE CANADIAN ENTOMOLOGIST. 07 



are found close to the compound eye, and behind the base of the antenna. 

 Usually they can be distinguished without denuding the head, but occa- 

 sionally they are so small, and the vestiture of the head is so thick, that a 

 part of it must be removed before the presence of the ocelli can be posi- 

 tively determined. 



The clypens is variously modified ; usually it is smooth, moderately 

 convex, and without any special peculiarity. In some cases, however, it 

 becomes prominent, bulging out between the palpi, and this convexity has 

 occasionally a concave depression in front, and in this depression again 

 are tubercles, conic protuberances, etc. In other genera a conic tubercle 

 adorns the clypeus; sometimes there is a cylindrical projection, and some 

 times the projection is flattened ; in one genus (Nonagris) bifid in front. 

 Occasionally the " infra clypeal plate " is produced, forming a flattened 

 shelf-like projection, usually squarely cut off before. These projections 

 are often partially or entirely concealed by the vestiture, but can in all 

 cases be readily demonstrated by touch with a fine pin. As to the gen- 

 eric value of these modifications, there is considerable difference of 

 opinion. For my own part, I consider them as having only a slight value, 

 and as not being sufflcient in themselves to separate genera. The genus 

 Cucullia, for instance, has in some species a normal clypeus, in others a 

 convex projection, and in others a depression in this convexity. Arzama 

 has in some species a conic tubercle, which is lacking in others ; so that 

 genera distinguished by clypeal differences only should be cautiously 

 created, and no genus based on the presence, absence or form of a tubercle 

 situated in a depression of the clypeus, should have any standing. 



The tongue varies somewhat in consistency and length. Sometimes it 

 is almost obsolete, as in Cleoceris and Eutkisa/iotia, but usually it is long, 

 strong and corneous, coiled between the palpi. Genera may be properly 

 based on the extremes of length and consistency of the tongue, but mere 

 variations in length do not authorize them. 



The palpi vary greatly, and genera are very largely based on their 

 modifications. In the typical Nodime they are of moderate length, the 

 second joint generally longest and always heaviest, and the third joint 

 usually small and slender, and sometimes so small as to be obsolete. 

 They are usually curved upward, closely applied to the head, and gener- 

 ally reach to the vertex. Sometimes they are so short as to be practically 

 obsolete, and then again they exceed the head by half the length of the 

 entire insect (§ Deltoidm). Sometimes they are porrect and closely scaled, 



