544 The University Science Bulletin. 



generally called the frons. In Lepyronia quadrangidaris there is 

 of course no median ocellus present, but if it were present it seems 

 highly improbable that it would be located on the ventral aspect 

 of the head, so far removed from the other two ocelli. Its position 

 would be more likely the normal one at about the place where the 

 tylus is located. 



The compound eyes (pi. LVI, fig. 1) are large but not very dis- 

 tinct on the dorsal aspect, due to the fact that their dorsal surfaces 

 are level with the vertex, and the color of both is somewhat the 

 same. They are oblong in shape, broader at the anterior end and 

 narrower towards the posterior. They are located in the extreme 

 caudolateral angles of the head. 



There are two ocelli (pi. LVI, fig. 1) present, located about mid- 

 way between the front and the pronotum and about as far from each 

 other as from the compound eyes. 



The antenncB (pi. LV, fig. 2) are located on the ventral surface of 

 the head in a hollow pit halfway between the eyes and the clypeus 

 and slightly cephalad of the eyes. In general appearance they are 

 small and inconspicuous, appearing to consist of a very short basal 

 stump and a long, thin, hairlike part which extends some distance 

 beyond the sides of the head. From specimens stained with eosin 

 and mounted on slides, more details of structure could be observed. 

 The basal segments, called collectively the shaft or peduncle, are 

 three in number. The first of these is subcylindrical, about as wide 

 as long, and is apparently the widest of the three. The second 

 segment is likewise subcylindrical, but approximately twice as long 

 as wide, with its basal end slightly narrowed and its broader distal 

 end cup-shaped. The last of the segments of the peduncle is the 

 shortest, oviform in shape, and fits into the concave end of the 

 second segment by means of a little stalk. The jiagellum or ivhip 

 consists of many segments, the exact number of which it was diffi- 

 cult to determine. After the first twenty-nine segments, extending 

 two-thirds of the entire length, the segmentation becomes indistinct. 

 In general these segments are cylindrical, but vary somewhat in 

 shape, being longer than wide toward the tip of the filament and 

 about equal in length and width at the base. The sense organs of 

 the antennae are located at the base of the filament and at the tip of 

 the third segment of the peduncle. They consist of a small group of 

 sensory pits, averaging about eight in number, and generally located 

 close to the apex and somewhat to one side of the segment. Appear- 

 ing to rise from the tip of this segment are three short, conspicu- 

 ous thick spines, which are also sensory in function. 



