1890.] 



THE YOUNG 



NATURALIST. 



23rd July.- 



-Eton ) W 



29th „ Folkestone [E 





f 0 



Stoney Stratford ) 



2nd Auq^. — Buckhurst Hill, 





Silverton, Essex 



4th ,, Dundee 



26th 



Harrogate 



Dartford 



27th 



Preston 



,, Gravesend 



28th 



Preston 





3 



One specimen is recorded from Ramsgate, one from Preston and 

 one from Glasgow without the dates. The captures by Messrs. 

 Williams and Oswald range from July 24th to August 6th. 



From this it will be seen that, with 4 exceptions, viz., Harrogate, 

 July 26th, Preston July 27th and 28th and Dundee August 4th, the 

 whole of the specimens taken north of Essex were taken before July 

 24th while the whole of the Kentish specimens were on or after that 

 date and the majority of them much after it. 



In the face of these dates I certainly fail to see how Mr. Tugwell's 

 theory (which is based on the records) that D. galii spread from Kent 

 by an instinctive daily progression in a certain direction , can be supported. 

 If anything is clear from these dates it is that the immigration, if 

 immigration it was, did not come via Kent, and that Mr. Tugwell's 

 suggested explanation of the cause of so great a proportion being taken 

 in that county fails. 



With the exception of the great good fortune which Messrs. 

 Williams and Oswald experienced, Kent in 1888 does not come out 

 so much better than other parts so far as imagines are concerned, and 

 I cannot help thinking that if in July 1888, two Entomologists had 

 watched for 13 evenings near the Wallasey sand hills, similar results 

 might have been obtained — a great part of the captures recorded else- 

 where appear to have been accidental and not the result of such 

 patient devotion as Messrs. Williams and Oswald's. 



Mr. Horne, in recording the Aberdeen specimen says (Ent. 21, p. 

 210) "I know of several specimens of this insect that have been found 

 near here during the past few years." How does Mr. Tugwell's 

 theory reconcile its presence in Aberdeen and almost entire absence 

 from Kent in those years. 



Then again, why should the " blown-over " theorists assume that 

 migration means always immigration. Is there any evidence that 

 migration in these days is always in a northerly direction and have 

 we as yet evidence that galii after all, is always so much more common 



