32 



THE YOUNG NATURALIST. 



[Fbbrttary, 



as 1888 would be the only one out of the eighteen -that have elapsed, 

 to bring them out ? I think that both these questions must be 

 answered in the negative. Galii is an insect easily forced in the pupa, 

 as witness five specimens in my possession which were collected as 

 larvae last September and hatched as imagine in November and 

 December. An insect so easily affected by temperature as this, would 

 surely have been developed on the sunny sandhills of the Cheshire 

 coast (where my specimens were taken), in less than eighteen years. 

 And if none of the other seventeen years would produce it, would the 

 cold season of 1888 be likely to do so ? I have not heard of any of 

 the larvae collected in 1870 remaining long in the pupa. Perhaps 

 some collectors who took specimens in that year will enlighten me if 

 such were the case. So far as I have learned, all or nearly all hatched 

 before the summer of 187 1 was passed. 



But there is another theory advanced by those who altogether 

 oppose the idea of migration ; it is that Galii is always with us, but 

 only plentiful in certain seasons. That from 1870 to 1888 there were 

 a few developed every year and that these were enough to keep up the 

 breed until a season came round which suited them, but at the same 

 time were so few that they escaped the diligent search of numerous 

 eager collectors. I hardly think that this idea will bear close investi- 

 gation. For let us suppose that at Wallasy, Cheshire (one of the 

 most abundant places for Galii both in 1870 and 1888), there have 

 been a few specimens bred every year, so few that none have been 

 found, although the said hills in this locality are visited by entomolo- 

 gists almost daily. And then in 1888 the larvae is taken in hundreds 

 if not in thousands. Now, let us consider some other localities where 

 Galii has been taken during last autumn. A few were taken in Ire- 

 land, a few at Warrington, a few at Cambridge, and in many other 

 places a few were taken. If now there were at Wallasy, in the years 

 '70 and '88, so few specimens that none were found, and these increased 

 to many hundreds ; how many would there be during the same time 

 at Warrington or Cambridge in order to produce, under similar cir- 

 cumstances, only a few specimens ? If this problem could be worked 

 out as a proportion sum, the answer would be that at those places 

 where a few larvae were found in '88 then were found in the years 

 '70 and '88 a fractional part of one specimen. And as Euclid says 

 " this is absurd." 



It will be very interesting to see how many wild specimens of Galii 

 are taken this year in the localities where the larvae were so abundant 

 last autumn. Although the search was diligently prosecuted many 



