26 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. 



The variation in the shape of the head and in its sculpture 

 is of the greatest importance for differentiating species, because 

 it is usually characteristic for both sexes. In order to condense 

 the descriptions and make them more accurate, names have been 

 applied to the various head regions and their boundaries. They 

 are as follows : 



Tentorial Fovea. The tentorial foveas are the pit-like open- 

 ings situated between the antennal sockets and the dorsal margin 

 of the clypeus. They mark the points of invagination for the 

 anterior arms of the tentorium. They vary from mere pits to 

 flaring, trumpet-shaped holes. 



Antennal Furrows. The antennal furrows, when complete, 

 extend from the tentorial foveas along the lateral margin of the 

 antennal sockets, thence across the cephalic aspect of the head 

 to near the lateral ocelli, thence across the dorsal aspect, and 

 finally end on the caudal margin just below the ridge separating 

 the dorsal and caudal margins of the head. While the antennal 

 furrows are frequently complete, yet certain sections are some- 

 times obsolete, so that it is desirable to refer to different sections 

 of the antennal furrows. 



Vertical Furrows. The vertical furrows are the portions of 

 the antennal furrows situated on the dorsal aspect of the head. 

 They extend from near the lateral ocelli to the caudal aspect 

 of the head. The vertical furrows are rarely wanting and are 

 usually more distinctly marked than the other parts of the anten- 

 nal furrows. 



Lateral Fovea. The portions of the antennal furrows ex- 

 tending between the vertical furrows and the antennal sockets 

 are sometimes completely wanting. The antennal furrows, in 

 many cases, instead of being entirely obsolete, are represented on 

 each side of the head by a distinct pit. These pits are known 

 as the lateral foveae. They are located near the antennal sockets 

 and may be connected with them by a short furrow. They vary 

 considerably in size, shape, and location. 



Ocellar Furrow. The ocellar furrow is a transverse furrow 

 extending between the ends of the vertical furrows near the 

 dorsal margin of the lateral ocelli. It is frequently confluent 

 with the space around the lateral ocelli. 



