58 



changes in question are the result of local circumstances, 

 and not referable to chance. The alteration in size I 

 have almost always observed to be from large to small, 

 and scarcely ever the reverse ; whereas in colour the 

 change takes place very nearly as much from light to 

 dark as it does from dark to light : nevertheless the 

 majority of instances I possess come under the latter 

 department. It has been remarked that all the speci- 

 mens of Mesites Tardii, which I captured in Devonshire, 

 were much smaller than the original series taken by 

 Mr. Tardy at Powerscourt Waterfall, in the county of 

 Wicklow ; and so decided was the difference, that many 

 of my friends, at first sight, concluded the two to be 

 distinct species. This, however, I consider entirely 

 owing to their locality, for my specimens were found 

 only on the coast, and Mr. Tardy's at a considerable 

 distance inland. And, inasmuch as neither of these 

 instances rested on mere individual examples, but on 

 long and conspicuous series, the certainty of the change 

 from large to small was the more apparent. Mr. Holme 

 of Oxford mentions having taken Olisthopus rotundatus 

 in the Scilly Islands, in great profusion, none of the 

 specimens of which exceeded two lines and a half in 

 length. At Whitsand Bay in Cornwall I have captured 

 Gymnaetron Campanula, none of which exceeded three- 

 quarters of a line, the usual length being from a line 

 to a line and three-quarters. Anthonomus ater, the 

 average length of which is two lines, I have taken a 

 series of in Lundy Island, none of which exceeded one. 



