Rmynehart — Life-History and Bionomics of the Flax Flea-Beetle. 523 



anteriorly at the vertex, from which there arise on rounded prominences 

 two long bristles. Posteriorly, and towards the median line, are two smaller 

 bristles, while posterior to these are two bristles of similar size to those on 

 the vertex. A further pair arises near the lateral posterior angle, just in 

 front of the mesothorax, and slightly dorsal and latero-ventrally at each side 

 is another bristle, All these bristles are supported by pap-like elevations of 

 the cuticle. The mesothorax is narrow, and carries four long bristles on 

 similar prominences. Its posterior margin is modified to form a slight point 

 at the median line, which projects posteriorly. This indicates the triangular 

 scutellum of the adult. The pupal cuticle is continuous over the mesotergum 

 and elytra, but underneath can be seen the sutures which mark the junction. 

 The metatergum is much broader than the mesotergum, and has the scutellar 

 groove distinctly shown as a longitudinal depression along the median line. 

 At each side of this groove there are two bristles, thus making a transverse 

 series of four. From tlie lateral angles of the metatergum the wings extend 

 backwards around the sides of the body towards the median line on the 

 ventral surface. The elytra extend similarly from the mesotergum, but the 

 wings, being longer than the elytra, project well beyond the extremities of 

 the latter. Just prior to emergence, the fine puncturing of the elytra is well 

 seen througli the pupal cuticle in suitably prepared specimens. 



The legs are folded on the ventral surface, as shown in PL XIX, fig. 38. 

 The front pairs are situate well forward, and are folded more or less trans- 

 versely, while the hind ones are directed backwards to project at the sides of 

 the posterior region of the abdomen. Each leg has near the knee a long and 

 a short bristle dorsally, and a single short bristle ventrally. There are ten 

 abdominal segments, nine of which are seen in dorsal view. Segments one 

 to six are very much alike, and of about equal thickness. As the body 

 tapers posteriorly, the sixth is much the narrowest transversely ; the greatest 

 breadth is attained by the second and third. Each of these segments has 

 near the posterior margin of the tergites a transverse row of strong bristles or 

 spines, which are supported on rounded prominences in the cuticle. Each 

 row consists of four pairs — two pairs being dorsal, one pair lateral, and the 

 fourth pair pleural and ventral to the spiracles. 



The seventh abdominal tergite is large, and is produced posteriorly to 

 form a rounded margin, which carries a transverse row of six long and two 

 minute spines. The eighth tergite when viewed dorsally is small, and only 

 projects slightly posterior to the seventh. It carries a similar transverse row 

 of bristles. The ninth tergite is prolonged into two strong, inwardly curved, 

 chitinised hooks, which resemble somewhat the forceps in the Eorficulidae. 

 These conspicuous structures serve definite purposes, which will be referred 



