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During a two years' stay in the West Riding of Yorkshire 

 Mr. Mansbridge gave his particular attention to certain well- 

 known and common species of lepidoptera, which are famous 

 for the melanic races they produce in that district. His 

 observations were principally carried on in the neighbourhood 

 of Leeds, but he occasionally visited noted collecting grounds 

 in the county. Referring to the area between Leeds and 

 Bradford, in which Horsford, the manufacturing village where 

 he resided, is situated, he stated that it is crowded with iron 

 works, forges, and mills ; whilst an almost unbroken string of 

 townships connect the two large centres referred to. In 

 consequence of this vast assemblage of smoke-producing 

 agencies, the atmosphere is heavily charged with murky 

 vapour, which in the neighbourhood of the forges is so dense 

 as to give one the impression of black fog. Much of this 

 smoke, he said, "is deposited directly on the trees in the 

 form of soot, and a great portion of the remainder is washed 

 down by rain ; thus giving rough surfaces, as tree boles and 

 stone walls, a permanent black coating, and the foliage is 

 so besmirched that autumnal tints in their full beauty are 

 unknown. In addition to the effect of the smoke, surfaces 

 are also rendered dark by the rain, which in spring is almost 

 constant : the rainfall for the district being about 36 inches." 



Mr. Mansbridge then proceeded to discuss the variation of 

 the species. Among the butterflies, he said, there was no 

 striking tendency to melanism ; females of Pieris napi were 

 darker, and, where represented, some of the Satyridse, such 

 as Epinephele ianira and E. hyperanthes, were duller than the 

 same species in the south; whilst, on the other hand, Erebia 

 cethiops was brighter than Scotch examples. The Heterocera 

 were considered at great length. Of the three species of 

 Sphingidge met with — Smerintlius populi, Ino statices, and 

 Zyg(B7ia lonicerce — none were darker than southern speci- 

 mens, and, except in the cases of Arctia lubricipeda and A. 

 nienthastri, both of which had larger and more numerous 

 spots, the Bombyces observed were similar to examples from 

 the south. Among the Noctuse and Geometrse, a number of 

 species exhibiting a greater or lesser tendency to melanism, 

 were referred to. In his concluding remarks Mr. Mansbridge 

 said that the extraordinary amount of smoke created in the 

 district led to a permanent darkening of the trees, etc., and 

 that this darkening was to some extent increased by the 

 high rainfall. Probably there was no other district in England 

 where the same conditions obtained to the same degree as in 

 the West Riding of Yorkshire, and it was a fact that as one 



