A. W. Rymer Roberts 203 



on the tentorium and with these plates the cardines of the maxillae 

 articulate at their posterior apices. From this point one pair of arms 

 extend, diverging somewhat, beneath the margins of the hypopharynx 

 to the inner margin of the mandibles. A second pair, more dorsal, extend 

 forwards, diverging outwardly towards the large flexor tendons of the 

 mandibles, but terminating abruptly with a number of short ligaments 

 before reaching them. 



The antennae are short and are situated at the anterior angles of the 

 head, close to the base of the mandibles. They consist of (1) a stout basal 

 segment, nearly twice as long as broad, rounded on the outer but almost 

 straight on the inner side, and bearing a rather long tapering seta not 

 far from the apex on the outer margin; (2) a second segment about two- 

 thirds the length of the first and more slender, widest near the apex and 

 bearing a short seta on the inner side of the apex; (3) two processes at 

 the apex of the second segment, borne separately, the ventral and shorter 

 one conical, very thinly chitinised and nearly colourless, the dorsal and 

 longer one more slender, yellow and strongly chitinised, about equal in 

 length to the second segment, though not more than half as broad. The 

 apex of the dorsal process bears a long stiff seta and also three minute 

 ones, all projecting forward, the first-named being longer than the pro- 

 cess itself. In Carabid and StaphyUnid larvae, where somewhat similar 

 processes are found on the antennae, Kemner(8) regards the longer pro- 

 cess as the terminal segment and calls the shorter ventral one "supple- 

 mentarglied." Gahan(6) has suggested that the latter is a sensory 

 organ. 



Three pores, which appear to have a sensory function, are present in 

 the basal segment. In the second segment a pore bearing a short spine 

 is present on the outer margin near the distal end, while another similar 

 pore may be found near the middle of the anterior margin. 



The eye is small, dark brown or black, situated laterally, a Uttle 

 below the base of the antenna. The chitin of the head is continued un- 

 interruptedly over it and is not raised. 



The mandibles are curved inwards and bear on their inner surface 

 two denticles. The first of these, situated near the apex, is flattened 

 dorsi-ventrally and overlaps the mandible of the opposite side when the 

 two are brought together, that of the right mandible usually, but not 

 invariably, overlapping the left. The presence of this denticle is charac- 

 teristic of the genus Agriotes amongst Elaterid larvae, though it is 

 present in certain other groups of coleopterous larvae. It is somewhat 

 rounded in outhne, though its anterior margin forms almost a right 



