202 Life History of Wireworms 



suture. AVithin the suture is a belt of strong yellow chitin, marked 

 transversely with striae similar to those forming the border to the other 

 segments. The remainder of the sternite is a semi-ovoid area strongly 

 chitinised and almost smooth. This encloses near its apex, posteriorly, 

 the cylindrical pseudopodium, which is by some considered to represent 

 the 10th segment. Surrounding the pseudopodium the 9th sternite is 

 convex and margined with a concentric border of fine striae in a some- 

 what darker yellow area. The pseudopodium itself is white, fleshy and 

 tubular and bears around its base a whorl of eight short, tapering, in- 

 curving hairs. It is situated somewhat anterior to the middle of the 

 9th abdominal segment. The anal aperture is linear and extends across 

 the pseudopodium in the longitudinal axis. 



The 9th tergite both above and beneath bears numerous rather long 

 yellow-brown hairs, which are more numerous towards the apex. The 

 9th sternite, anterior to the pseudopodium, has a transverse row of six 

 hairs, the two median ones of which are shorter and slightly anterior to 

 the rest. A single short hair is also usually present on either side of the 

 pseudopodium. 



Head and Mouth-parts of Larva. 



On the dorsal surface of the head there is a cephalic plate, expanded 

 anteriorly over the base of each mandible, tapering posteriorly and end- 

 ing in a point in the occipital region (Fig. 2 a). Doubtless it is composed 

 of several fused sclerites, probably the frons, clypeus and labrum. 

 Laterally it is separated from the epicranial plates by a deep suture. 

 In Agriotes, and apparently also in Cardiophorus, the epicranial plates 

 meet for a short distance at the base of the head (vertex) behind the 

 cephalic plate, though in most Elaterid larvae the apex of the cephalic 

 plate extends backwards to the posterior margin of the head and the 

 epicranial plates are dorsally entirely separated by it. On the ventral 

 surface the cephalic plates are fused together posterior to the base of 

 the hypostome and though there is little sign of a suture in the median 

 line, there is a distinctly darker line ventral to the tentorium which 

 probably represents the line of junction. There appears to be no true gula. 



In its general plan the structure of the tentoritmi is simple. On the 

 floor of the head at the base two arms extend for a short distance on 

 either side, almost parallel to the thickened margin of the occiput. From 

 the occiput the main longitudinal trunk is carried forward by two beams, 

 closely approximate, on the floor of the head to the base of the maxillae. 

 At this point two small plates of thickened brown chitin are developed 



