PEOTiETIA. 137 



emarginate. Prothorax with the base inclined on each side and 

 abruptly emarginate in the middle. Scutellum moderately long, 

 with the apex blunt and rounded. Elytra sinuated laterally behind 

 the shoulders, with the apical angles acute, frequently spinose. 

 Front tibia ax*med with two or three short teeth, except in the d" 

 of P. albogiUtata. Hind tibia truncated at the end. Sternal 

 process short and flattened, widened in front of the middle coxse and 

 straight or broadly rounded in front, except in P. confusa. 



Except in P. albogntlata, the sexes are closely similar and the 

 abdomen is rai-ely excavated or arched in the male. The spurs 

 of the hind tibiae, however, are always shorter and sharper in that 

 sex, and the last ventral segment is smoother. In some of the 

 species the anterior edge of the clypeus bears two recurved teeth 

 which are feebler or quite absent in the female. 



This is a very large and polymorphic genus, which may be 

 regarded as the central mass of the subfamily froui which other 

 genera diverge iu all directions. Such a niass is found in nearly 

 every large group and the difficulty of fixing its limits is invariably 

 very great. Tentative efforts to divide it into smaller genera are 

 often made, but are generally doomed to failure as the number of 

 known species increases. In the present case numerous so-called 

 genera have been formed for single species, or upon the strength 

 of features peculiar to one sex, and I have found it necessary to 

 abandon several of these which have failed to stand the test of 

 tabulation. 



In the key which follows, one species, P. alboguttata, Vigors, is 

 omitted, because it is difficult to find any features, except colour 

 and marking, which are common to the two sexes and which 

 would not be liable to mislead if used for the purpose of tabula- 

 tion. Such marked dimorphism is entirely abnormal iu the 

 present genus, and it would be desirable to form a new genus or 

 subgenus for this species but that the female presents no really 

 distinctive characters, and indeed is very similar to P. lonrji- 

 pennis, etc. 



Key to the Species. 



1 (16) Surface of the body without opaque 



bloom. 



2 (15) Surface of the body metallic. 



3 (10) Thorax (and generally the whole body) 



Avithout pale markings. 



4 (5) Surface not very shining cuprea, F., p. 130. 



5 (4) Surface very shining. 



6 (7) Legs green or blue pretiosa, Nonf.,p. 141, 



7 (6) Legs fiery red. 



8 (9) Elytra without transverse pale markings, atiripes, Hope, p. 141. 



9 (8) Elytra decorated with transverse pale 



markings wow^aMa,Nonf.,p.l42. 



10 (3) Thorax decorattid with pale markings. [p. 143. 



11 (12) Thorax decorated with minute spots . . orientalis, G. &P., 



12 (11) Thoraa: decorated with irregular patches. 



