2 



THE YOUNG NATURALIST. [Jan 



THE BLOWN-OVER THEORY, 



BY C. A. BRIGGS. 



I hope that my friend, Mr. Tugwell will forgive my pointing out 

 that even his fresh argument is not conclusive. 



His idea seems to be that as Kent is the nearest coast to France 

 the wave of immigration (presumably from the sand hills opposite) 

 strikes there first and more specimens lodge in that County than in 

 any other, radiating thence to less favoured localities. For he tells 

 us " We see that in Kent we get a much greater number of caught 

 specimens than elsewhere and from here they spread out until Scotland 

 and Ireland are reached by a few." He also says " No one presumes 

 that this flight (i.e. to the Wallasey sand hills) is one straight and 

 continuous effort but would be reached by probably an instinctive daily 

 progression in a certain direction. ," 



Let us pass over for the moment the question of the comparison of 

 the number of Kentish as compared with other specimens. 



His invasion theory certainly has a plausible look so long as we, 

 as he does, only have regard to places and not to dates but if it has any 

 real foundation the Kentish dates should be the earliest and the rest 

 progressively later the farther the distance from Kent — But what are 

 the facts ? 



Recorded for 1888 in the Y.N. the E.M.M. and the Entomologist 

 we find, I think, but 43 specimens distributed as follows, Scotland 3 

 Ireland 1, Cumberland 1, Durham 2, Lancashire 5, Yorkshire 2, Derby 

 2, Bucks 2, Essex 2, Middlesex 1, Kent 21, and Cornwall 1. Of the 

 Kentish 21, Messrs. Williams and Oswald's are 17, leaving only 4 

 for the rest of perhaps the most thoroughly worked county in England. 



These numbers differ but vary slightly from those given by Mr. 

 Tugwell but I cannot find the records of those he alludes to from 

 Suffolk, Norfolk, or Deal. 



Arranged in order of date the record is 



13th June. — Penryn, Cornwall 

 1 6th July. — Howth, Ireland 

 17th ,, Aberdeen 

 1 8th ,, Hartlepool 

 19th ,, Scarborough 

 20th ,, Hartlepool 



20th July — Middlesex 

 21st ,, Manchester 



,, ,, Carlisle 



,, ,, Derbyshire 



,, ,, Derbyshire 

 22nd ,, Rossall, Lancashire 



