291 



section that I am now dealing with. At the present time, 

 then, species attributable to this aggregate have been describ- 

 ed under nine names. Of these nine names one (P. Giicrini, 

 Breme) cannot be confidently identified with any insect by 

 the description, which however (such as it is) would fit J\ 

 tristis. Germ., fairly well. (Germar's the later name.) 



The follov/ing table shows characters by which the Ptcro- 

 helc^i of this group can be distinguished inter se, with the ex- 

 ception of P. Guerini, Breme, concerning which there is not 

 sufficient information available for its inclusion : — 



A. Joint 6 of antennse not or but little 

 dilated on outer margin, never decid- 

 edly transverse. 

 B. Alternate striae of elytra much deeper 



than the other striae 

 BB. Elytra not having alternate striae 

 deeper than the rest. 

 C. Elytra much more nitid than CC. 

 D. Lateral margins of pronotnm 



very feebly explanate ... 

 DD. Lateral margins of pronotnm 

 strongly explanate. 

 E. At least all the alternate in- 

 terstices of elytra cqnspicn- 

 ously and regularly granulate. 

 F. Prothorax twice as wide at 

 base as in front. Size large 

 FF. Prothorax much less nar- 

 rowed in front. Size mode- 

 rate 

 EE. Front and inner parts of 

 elytra not (or only sparsely) 

 granulate. 

 F. Pronotnm sparsely and 

 faintly punctulate. 

 G. Size large. Surface only 

 moderately nitid. Late- 

 ral area of pronotum 

 wide and flat 

 GG. Size small. Surface quite 

 nitid. Lateral area of 

 pronotum narrower and 

 concave 

 FF. Pronotum closely and 

 strongly, though finely, 

 punctulate ... 

 CC. Elytra notably more opaque. 

 D. Explanate margin of elytra 

 wide (at base as wide as apex of 

 front tibia) 

 DD. Explanate margins of elytra 

 much narrower. 

 E. Ventral segments with scarcely 

 any trace of longitudinal 

 wrinkles 

 j2 



insignis, Blockb. 



simplicicollis, BJachb. 



granuliger, Mad. 



;ul 



regularis. 



Bhicl-b. 



tristis, Germ. 



nitidiusculus. Marl. 



gracilicornis. BJnd-h. 



granulatns. Gorm. 



ventralis. BJncl'h. 



