2188 The Zoologist — June, 1870. 



one or two per cent, of the radiant energy consists of visible rays, the rest is 

 either invisible heat or actinism ; in other words, more than ninety-eight per 

 cent, of the gas is wasted in producing rays that do not help in making objects 

 visible." 



Mr. G. R. Crotch sent for exhibition British specimens of four species of 

 Dasytidae ; one being DoUchosoma protensa, taken some years ago in the Isle 

 of Wight, and agreeing entirely with Spanish specimens taken at Carthagena ; 

 the other three belonging to the subgenus Mesodasytes, and having a somewhat 

 complicated synonymy. The following note was read respecting them : — 



" The old genus Dasytes has been subdivided by Mulsant and Rey into five 

 subgenera ; all our species, except the rare D. niger, fall into the third of these, 

 called Mesodasytes, of which three species are described from France, all of 

 which are found also in England. Mulsant's nomenclature is by no means in 

 accordance with Kiesenwetter's, and he seems not to have noticed Kiesenwetter's 

 paper on the Spanish Melyridae in the eleventh volume of the Berlin Zeit- 

 schrift. Thomson again appears to be at variance both with Mulsant and 

 Kiesenwetter, so that the group is somewhat confused. The synonymy 

 appeai-s to me to stand thus : — 



1. Dasytes oculatus, Eies. (1867) = coxalis, Muls. (1868) = plumbeus, III., 

 Thorns, (nee Miill.) 



2. D. plumbeus, Mull, Eies. = flavipes, Oliv., Muls. (nee Fab.) = fusculus, 

 Thorns. ? (nee Kies.) 



3. D plumbeo-niger, Goeze = seratus, Ste. = aerosus, Kies. = plumbeus, 

 Oliv., Fourc, Muls. (nee Miill.) = subaeneus. Thorns.^ Crotch Cat. (nee Schonh.) 



The three species have a considerable resemblance in form and colour. 

 D. plumbeo-niger may be known by its concolorous antennae and legs. The 

 males of D. oculatus are distinguished by the large globose eyes, the space 

 between which is much naiTower than in D. plumbeus : the females are more 

 difficult, but in D. oculatus the base of the antennae and the anterior coxae are 

 testaceous, wbile in D. plumbeus only the second joint of the antennae is 

 testaceous, and the eyes are less developed in the latter species. I have 

 received from M. Eichoff specimens of D. aerosus, Kies., which agree perfectly 

 with the common English species, aeratus, Ste., which, however, will take 

 Goeze's name, plumbeo-niger; Kiesenwetter appears formerly to have con- 

 founded it with D. plumbeus. The range of the three species in England 

 requires further observation ; my specimens of D. oculatus are all from Mr. 

 WoUaston, who found them in Lincolnshire, while my D. plumbeus are from 

 the neighbourhood of London. It seems very probable that more species of 

 the genus Dasytes will occur in England ; D. obscurus, GylL, can hardly be 

 wanting, and the true D. subaeneus may be confidently expected, and may at 

 once be known by its tarsi, which exceed the tibiae in length." 



