On the Classification of the Rutelidse. 363 



XL. — Notes on the Classification of the Coleopterous Family 

 Rutelida?. By Gilbert J. Arrow, F.E.S. 



The following notes upon points which have arisen in the 

 course of work upon the collection of Rutelidfe in the British 

 Museum will, I hope, contribute something to the more 

 perfect classification of that beautiful and interesting group of 

 beetles. 



The mass of species forming the Central and South- 

 American group of the Antichirides is in much need of 

 generic arrangement. Insects of very diverse characters have 

 been assigned to tlie genera Antichira and Chlorota', and 

 althougli various new genera have been formed from these 

 assemblages, the species have not yet been tabulated, and 

 those remaining in the older groups are little less hetero- 

 geneous than before. 



A genus Ptenomela was described by Bates for tlie recep- 

 tion of " a considerable number of species which differ con- 

 stantly from Antichira in the form of the mandibles (unarmed 

 externally), from Thyridium in the size and shape of the 

 scutellura, which is one fourth the length of the elytra and 

 triangular, with flexuous sides, and from Chlorota in the 

 well-developed mesosternal process." The only species men- 

 tioned by the author is gratiosa, Sliarp. With this the 

 following insects are congeneric : — 



P. (Thyridium) sodalis, Watcrh. P. (Thyridium) Blanchardi, Kirsch. 



P. (Chlorota) euchloroides, Murr. P. (Thyridium) scutellata, Waterh. 



P. (Antichira) psittacina, Burm. P. (Thyridium) punctata, Waterh. 



P. (Dorystethus) glauca, Bl. P. (Antichira) geuerosa, Waterh. 



Two insects at present left in the genus Antichira, viz. 

 A. j)uherula and A. pilosula of Waterhouse, should be trans- 

 ferred to Thyridium, which is distinguished by the small 

 heart-shaped scutellum, concave on its front margin, into 

 which a rounded lobe from the hinder edge of the pronotum 

 fits. 



Antichira sulcipenm's, Waterh., has some resemblance to a 

 Thyridium, but differs conspicuously, and a new genus must 

 be found for it. The type is the only specimen of this 

 genus known to me. It is a highly peculiar insect with 

 strongly sulcate elytra, very small scutellum, scarcely longer 

 than it is broad, and the prothorax sharply angulated at the 

 sides and without a lateral border. In the last character it 

 differs from every other known member of the present group. 

 The generic diagnosis is as follows : — 



