1144 Insects. 



Now, assuming (as I think, from observation, we may fairly do) that Cossonus Tardii 

 is strictly confined to the warmer parts of Great Britain, — and taking also for granted 

 the fact, that the high parts of the coast of Devonshire facing the Bristol Channel, from 

 their being exposed to the north winds, are much below the average temperature of 

 the rest of Devonshire, and therefore cannot possibly be classed with the " warmer " 

 portions of our island, — I say, if the first of these conditions be true, Cossonus Tardii 

 could not exist on the high lands of the north of Devon. And therefore when, having 

 taken the first assumption into consideration, I came round to this point of my argu- 

 ment, I should certainly (as before intimated) have been much perplexed how to 

 account for the similarity of the two cases, had that similarity existed. Fortunately, 

 however, it does not ; for, had I found Cossonus Tardii in the north of Devon, as I 

 did in the south, inhabiting exclusively the highest points, — the simple question, 

 " Why an animal, the inhabitant of a warm climate, when placed in a cold one, should 

 fly to the coldest points in preference to the warm ?" — is, I confess, a problem which 

 I should have been unable to solve. There is, perhaps, one question which might be 

 asked on the other side, and, inasmuch as I think it is the only one left, it is the last 

 I shall touch upon. It might possibly be suggested, " If Cossonus Tardii is strictly 

 peculiar to a warm climate, why, in the south of Devon does it not remain in the val- 

 leys instead of ascending the hills ? " To which I would reply, that the air of the 

 south of Devon is so exceedingly mild, and even the highest ground on the coast always 

 protected from the north winds by still higher inland (as, for instance, the coast of 

 Devon is protected, principally, by Dartmoor Forest, and that of Cornwall, by the high 

 range of hills running from north-east to south-west, completely through the county), 

 that I think it questionable whether, in reality, the valleys, although undoubtedly 

 more luxuriant, are much warmer than the hills. It should be remembered also, that 

 there nearly every valley has its own stream, which, although it may give increased 

 verdure, would not always, especially in the winter, add to its warmth. So far indeed 

 as my own experience goes, I have always found the hills on the south coast but very 

 slightly colder than the valleys. And, furthermore, the insect may prefer dry situa- 

 tions to damp ones, and consequently may put up with the inconvenience of a slightly 

 cooler temperature in order to avoid the moisture. The case of the northern speci- 

 mens is apparent. It was indeed an extreme one, when they had to ask themselves 

 the question, — "What shall we do, — shall we endure extreme cold or excessive mois- 

 ture ? " Now we have shown (or rather endeavoured to show) that in " extreme cold " 

 they could not exist ; therefore their answer must have been unanimous, — " Excessive 

 moisture." Had indeed the climate of the south of Devon been suddenly transported to 

 the north, my own opinion is they would gladly have worked their way upward, as quick- 

 ly as we can imagine a Curculio so sluggish as the Cossonus to ascend the sides of an 

 alpine pass. But this did not take place. Hence the " universality " of their reply. 

 Thus it will be seen, from the previous remarks, that the captures of Cossonus Tardii 

 in 1844 and 1845, although as to local circumstances, at first sight, apparently incon- 

 gruous, do not in reality militate. Although separated by a distance of nearly ninety 

 miles, they were both strictly maritime; — both found in the greatest profusion and in 

 the same species of tree ; — both peculiar to a warm climate ; — and both (as I trust 

 the above observations will show) in every respect identical. — T. Vernon Wollaston ; 

 Jesus Coll. Cambridge, July 23, 1845. 



Occurrence of Limnceum nigro-piceum in the Isle of Wight. Seeing a note in the 

 'Zoologist' (Zool. 1043) respecting Limnceum nigro-piceum, I beg to inform you 



