148 r Jul y> 



PRYLLOTRETA DIADEMATA, Foudr. : 

 AN ADDITION TO THE BRITISH LIST OF COLEOPTERA. 



BY E. A. NEWBERY. 



The small group of the genus Pl/i/Uotreta with entirely hlack 

 elytra and pale basal joints to the antennae is a difficult one to diffe- 

 rentiate, and it is with some hesitation that I venture to bring forward 

 the above insect as British. 



Capt. Sainte Claire Deville, however, assures me that the speci- 

 mens I sent him for corroboration are undoubtedly the P. diademata 

 of Foudras, which should therefore find a place in our list. He 

 suggests that P. crassicornis, All., is also very likely to occur in 

 Britain ; it is, on this account, included in the following table : — 

 A. Antennae (relatively short) with 1st joint, entirely red ; 5th joint notably longer 



than 4th. On Iberis amara. L., 1 5 mm [P. crassicornis, All.]. 



AA. Antennae with 1st joint black or spotted with black above, or at the base ; 4th 

 and 5th joints not disproportionate, 

 a. Head punctured solely on a transverse zone going from eye to eye ; punctures 



of elytra strong, close, and confused. L., T8 mm.... 



P. diademata, Foudr. 

 aa. Head more or less entirely punctured. 



b. Punctuation of elytra coarser and more regular, almost in lines, es- 

 pecially near base j average size larger. L., T8 — 2 mm.... 



P. atra, F. 

 bb. Punctuation of elytra finer, close and confused ; average size smaller. 

 L., 1*5 — 1*8 mm. ... P. serea, All. (= punctulata, Brit. Colls.). 

 The construction of a satisfactory table is not an easy matter, 

 owing to the contradictory statements of authors. The above, in the 

 main, is taken from that of Bedel (Faune Seine, v, pp. 184-5) ; but 

 the characters derived from the punctuation of the head made use of 

 by Foudras, Allard and others, do not appear to be sufficiently con- 

 stant to be relied on. P. atra and cerea are easily separated by the 

 table ; P. diademata is about the size of P. atra, with the close and 

 confused elytral punctuation of P. area, which, however, is much 

 coarser than that of the latter species. 



The only specimens of P. diademata that I have seen were taken 

 by my friend Mr. P. de la Garde in several localities in South Devon. 

 Capt. Deville tells me that it is not rare in France (except in the 

 south) on Cardamine pratensis in humid woods, &c, from April to 

 June ; he believes that it also occurs on some of the species of 

 Nasturtium . 



12, Churchill Road, Dartmouth Park, N.W. : 

 June 15th, 1908. 



