RYLYmmkKV— Life- History and Bionomics of the Flax Flea- Beetle. 517 



bristle-bearing areas or plates occurring on the metathorax area : a narrow, 

 transversely elongated plate having a median longitudinal suture and pro- 

 vided with a single bristle at each side, on the prescutum ; lateral to this 

 plate is a small triangular-shaped one devoid of bristles ; the united scuto- 

 scutellum has dorsally a plate similar in construction and armature to that of 

 the prescutum, while lateral to it at each side a single bristle-bearing 

 triangular-shaped plate occurs ; ventral to this and extending longitudinally 

 across the segment is a large crescent-shaped plate, with one large bristle at 

 the posterior end, a larger bristle medianly, and two minute bristles anteriorly- 

 This plate occurs on the alar lobe, and the bristles on it may be referred to as 

 the alar bristles. Ventral to the alar lobe, towards the posterior margin, is 

 a small plate bearing a single bristle. From the position of the spiracle this 

 may be regarded as the homologue of the plate occurring on the epipleural 

 lobe of the abdominal segments, and its bristle is therefore the epipleural 

 bristle of the mesothorax. Anterior to this is the plate in which the spiracle 

 opens. It is roughly triangular in shape, and the anterior angle carries a 

 small bristle. 



On the metathorax the arrangement of the bristle-bearing plates and 

 bristles is exactly similar. Here, however, the alar-lobe plate is larger, and 

 the spiracular plate has not a visible spiracle, thus differing from other 

 Chrysomelid larvae, e.g. Donaciae, inasmuch as the latter, according to Boving, 

 possess on the metathorax a pair of "small, impenetrable, and useless 

 spiracles (5). 



The legs are placed latero-ventrally towards the posterior margin of the 

 segments on prominent coxal (hypopleural) lobes. The thoracic sternites are 

 imperfectly divided, and the different areas difficult of determination. The 

 sternum of the prothorax has two large plates fused at the middle line and 

 provided with one pair of fairly large bristles near the median line and 

 towards the post-sternellum. The meso-sternum carries a pair of large fused 

 plates anteriorly. These bear a single pair of bristles, and, towards the 

 posterior angles, a pair of minute punctures. The post-sternellar region has 

 a small triangular plate at each side of the median line provided with a single 

 minute bristle. The meta-sternum is similarly strengthened and armed, but 

 the anterior plates are usually smaller. 



(iv) Legs (PL XVII, figs. 16 and 19). — These are all about equal in size, 

 short and stout. They appear to be composed of segments homologous with the 

 coxa, trochanter, femur, tibia, and tarsus of the adult. The coxa articulates 

 with a large flattened, chitinised acetabulum, which is supported by the coxal 

 lobe. Anteriorly the acetabulum is strengthened by a thick band of chitin, 

 which passes laterally as a ridge. This is armed with usually two, but 



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