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THE LEPIDOPTEROUS FAUNA OF LANCASHIRE 

 AND CHESHIRE. 



By JOHN W. ELLIS, L.R.C.P., L.R.C.S.E., 



Liverpool; Hon. Sec. Lancashire and Cheshire Ejitomological Society. 



One of the main factors which determine the geographical distribu- 

 tion of phytophagous insects being the presence or absence of the 

 plants upon which they subsist during a portion, if not the whole, of 

 their existence, and as the flora of a district depends very largely upon 

 the geological formation and meteorological conditions of that 

 district, an apology is scarcely needed for referring very briefly to 

 these conditions as they exist in the counties of Lancashire and 

 Cheshire, before commencing a list with localities of the lepidopterous 

 fauna of these counties. 



Exposed as they are to the prevailing warm and moisture-laden 

 south-westerly winds, and washed as a portion of each county is by 

 the waters of the Irish Sea, the average yearly temperature is always 

 several degrees higher, and the annual rainfall from lo to 20 inches 

 greater, than that of the corresponding east coast of England. 

 Throughout Lancashire, with the exception of the extreme north, 

 w^here the rainfall is somewhat higher, the amount of rain varies 

 between 30 and 40 inches yearly, while over the whole of Cheshire 

 the average is between 20 and 30 inches. 



The two principal geological formations met with belong to the 

 Triassic and Carboniferous periods; the former, including the series 

 of New Red Sandstones, occupying the whole of Cheshire west of 

 Stockport, and the western half of Lancashire, including the Preston 

 and Fylde districts, but not including the extreme north, to be 

 afterwards alluded to. 



The Carboniferous system, chiefly the upper and lower coal 

 measures and the millstone grit, extends over the eastern half of 

 Lancashire, forming the great coalfield of this county, and the extreme 

 east of Cheshire is also occupied by a continuation of the same beds. 

 Only in the north of Lancashire, in the neighbourhood of Grange, 

 and in the extreme north-east, does the mountain limestone appear ; 

 and, as will be afterwards seen, the district of Grange assimilates 

 more closely in its entomological fauna to the south of England than 

 does any intervening district. 



Through a large portion of both counties the Western Trias is 

 separated from the Eastern Carboniferous series by a narrow strip of 

 Permian Limestone, nowhere more than a mile in breadth, and 

 stretching due north and south through Stockport and a few miles 

 east of Manchester. In most places the new red sandstone is 



Feb. 1885. 



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