196 Life History of Wireworms 



but under the microscope can be seen to bear numerous short irregularly 

 shaped striations. The sternites are smoother. 



The segments of the body are cylindrical or nearly so, but the head is 

 flattened dorso-ventrally and is somewhat darker in colour than the 

 remaining segments. 



The setae are slightly yellowish and all are shorter than the segments 

 to which they belong. The setae of the posterior row are longer than those 

 of the anterior, as in older larvae. 



The marginal striae at the base of the 2nd and 3rd thoracic and of 

 the abdominal segments are very fine, but are visible under the micro- 

 scope. Similarly, those forming the anterior and posterior margins of 

 the prothorax. 



The nasale, or clypeal process, is now trifid, with a stout median 

 dens and a smaller lateral dens on either side of the median one, scarcely 

 haK as long and little more than half as broad as the median one. Ventral 

 to the nasale the semi-lunar process over the mouth, described in the 

 older larva, can now be identified. In the specimen in which it was found 

 four or more teeth could be seen, the remainder being represented by 

 the sinuate margin of the process. The proportion of length to breadth 

 of the mandible now nearly corresponds to that of the full-fed larva. In 

 the antenna the dorsal process at the apex is still proportionately longer 

 than in the late stages, being about one and a half times the length of the 

 2nd segment. 



The spiracles are now distinctly margined by a brown peritreme, 

 which however is pale and very narrow on the anterior margin of each 

 respiratory orifice. The posterior margin is also narrow but more distinct. 

 The lateral margin and also the central septum are broader than those 

 of the first instar and furnished with pittings or corrugations correspond- 

 ing to the number of teeth which project from the sides of each orifice. 

 These number eight or nine in the abdominal and eleven in the thoracic 

 spiracles. 



The stigmatic scar is visible as a colourless strand in the chitin placed 

 at an obtuse angle to the axis of the spiracle and dorsal to it. The inner 

 end is attached to the atrium, while the outer terminates in a slightly 

 divaricate fork in the cuticle. 



The 9th abdominal segment is subparallel at the sides for nearly two- 

 thirds of its length. It then tapers sharply to the apex, from which the 

 Cauda is produced. The latter is distinct, sharply pointed and in colour 

 tinged with yellow. 



The sensory pits are bordered by an ochraceous rim which is elevated 



