16 



BULLETIN OF THE BUREAU OF FISHERIES. 



yellow in color, spotted with dark brown. On the ventral surface the spots cover 

 the whole of the basal portion and extend forward in two long points on either side. 

 There is also a narrow band of spots across the base of the lower lip. On the dorsal 

 surface the spots cover the basal portion behind the eyes, and there is a large patch 

 behind and inside of each antenna (fig. 8) . 



The eyes (e) are six in number on either side and are situated outside the bases 

 of the antennas and behind the mandibles. Each group of six is arranged in two 

 transverse rows, somewhat concave toward each other hke parenthesis marks. 

 The interval between the two outside eyes is longer both longitudinally and trans- 

 versely than between the two inside ones. Each eye is elliptical in outhne, the 

 long axes of the ellipses in the two rows inclined toward each other. The chitin 

 integument over each eye is transparent, and beneath it can be seen the retinal 

 pigment, which is uniformly black. In larvae taken from the pupal chamber this 



black pigment entirely disappears, the eyes being apparently withdrawn prepara- 

 tory to forming the compound eyes of the adult. 



The antennas (an, figs. 8 and 9) project from the dorsal surface of the head be- 

 hind the inner corners of the bases of the mandibles. Each consists of a basal 

 joint and three terminal joints, the former twice as long as the three latter combined 

 and three times their diameter. The basal joint carries a fringe of long hairs along 

 its inner margin and much smaller and widely scattered hairs over its entire surface. 

 The three terminal joints are destitute of set as and hairs (fig. 10). 



The mandibles (md, figs. 8 and 9) are not alike ; the right one is always longer and 

 more slender than the left, and the tooth on its inner margin is very much larger 

 and bifid at the tip (fig. 11) . Indeed, the tooth on the left mandible is hardly more 

 than a small spine on the inner margin, and even that is sometimes wanting. The 



Fig. 11. — Dorsal view of mandibles. 



Fig. 12. — Ventral view 

 of left maxilla. 



MOUTH PARTS. 



