WILLIAMS: LARRID^ OF KANSAS. 127 



1902) we read that, "in the more specialized orders, wherever 

 we have been able to distinguish between the front and the 

 vertex, we have found the paired ocelli in the vertex." The 

 solid line /, figure 6, probably represents the upper limit (on 

 the median line) of the frons and the lower limit of the vertex 

 (vx), from a morphological point of view, while the paired 

 dotted lines / and vx, in the same figure, represent these two 

 areas as frequently considered by the systematist. Behind 

 the paiied ocelli is a somewhat wedge-shaped depression point- 

 ing posteriorly. This may mark the posterior limit of the 

 vertex. This depression is well marked in those genera among 

 the Larridae having the posterior ocelli distorted, and is ap- 

 parently associated with that distortion. 



Geng; mid Occiput. The gense, or cheeks, refer to that por- 

 tion of the head behind the compound eyes, and limited poste- 

 riorly by the occipital ridge. The occiput is represented by a 

 more or less circular depression* occupying the posterior por- 

 tion of the head and opening into the foramen magnum, which 

 is the passage for the esophagus, trachse, etc., from the thorax 

 into the head. It is evident from descriptions of species, and 

 from generic descriptions as well, that at least the dorsal por- 

 tion of the occiput is not usually considered as confined by the 

 raised line bounding the depression, but that it extends more 

 anteriorly, viz., as far as the line drawn from the posterior 

 borders of the eyes, to meet the vertex. 



Ocelli. These are three in number, but in Tachytes, as in 

 other typical Larridse, only the anterior one is rounded, per- 

 fect, and presumably functional; the posterior ocelli in the 

 species under consideration are drawn out and curved hook- 

 like behind, where they are quite proximate. A smooth, 

 shining area extends along the outer edge of the attenuated 

 ocelli but does not seem to be a portion thereof, for if the part 

 of the head containing the ocelli be submitted to the caustic 

 action of KOH, and then exposed to light, the nearly circular 

 outline for the anterior ocellus is revealed, while the posterior 

 pair show elongate, imperfectly S-shaped slits. 



Appendages. 

 Antennie. (PI. XXVI, fig. 41.) The antennse, as heretofore 

 noted, arise close together from the frons, just above the 

 clypeus. They consist in the male of thirteen joints, and in the 



* This is referred to in Say's American Entomology as the jugulum. 



