944 Insects. 



this was not the case : I placed in the bottle an abundant supply of the freshest grass 

 and other plants which grew close to the spot where they occurred, so that it was no 

 matter of compulsion on their part, but pure and decisive choice. Not having watched 

 their progress, it is certainly possible that the Coleoptera may, in the first instance, 

 have urged civil war amongst themselves, and have thus lessened their numbers before 

 the snails joined in the fray. Indeed, it is highly probable that such was the case, 

 but still the solution is a difficult one, without assuming that the snails had, at all 

 events, a large share of the booty. For, regarding the small remaining specimen of 

 Ptomophagus velox, surely no one will suppose him guilty of a deed so atrocious, 

 that, after having murdered three dozen of his brethren, for the most part stronger and 

 bigger than himself, he should actually sit down in cold blood, and feast upon their 

 mangled carcases until all were consumed ! The number of specimens captured were 

 four of the common Helix cantiana, five of hispida, and one of virgata. Of the 

 Coleoptera there were certainly not less than three dozen, including specimens of 

 Dromius agilis and 4-maculatus, Helops striatus, Haltica 4-guttata, Apion Sorbi, 

 Phaedon Vitelline, &c, besides several species of Brachelytra, not a fragment of 

 which (with the exception of the above-named specimen of Ptomophagus velox) now 

 remains. I have carefully examined the bottle, and, although I have twice emptied 

 the contents on a white sheet of paper, and searched with the greatest care, I cannot 

 discover the smallest trace of the former inmates, which can be accounted for only on 

 the hypothesis that the snails took an abundant part in the fray ; for, even supposing 

 that they did not commence the fight, events certainly prove that they had the best share 

 of the booty. — T. Vernon Wollaston ; Jesus College, Cambridge, March 6, 1845. 



Occurrence of Papilio Machaon in Derbyshire. As I find the capture of two spe- 

 cimens of the swallow-tail butterfly {Papilio Machaon), at Matlock, in Derbyshire, 

 recorded in a former number of ' The Zoologist' (Zool. 400), I feel myself bound to 

 explain how this must have happened ; the passage was pointed out to me only a few 

 days ago, or I should certainly have sent this explanation sooner. In the springs of 

 1843 and 1844, I procured a very large number (many hundreds) of the chrysalids of 

 P. Machaon from Burwell Fen, and as the butterflies came out, by far the greater 

 number of them were permitted to escape, partly for the pleasure of seeing them in the 

 state of liberty, and partly in the hope that they might breed and continue to flourish 

 in the neighbourhood ; at the same time, by so doing, they would disprove the common 

 notion that local insects cannot be permanently transplanted. Most of those so turned 

 out were at Matlock, but many were also liberated at Beeston, in Nottinghamshire, and 

 some few dozens at Eton, in Buckinghamshire. I had the best prospect of success at 

 Matlock, as there is not much mowing grass, whilst various umbelliferous plants abound 

 on the rough grounds, and although the features of the country are the extreme oppo- 

 site to those of Cambridgeshire, I was not without hopes, for I had heard that on the 

 continent P. Machaon is found on hills : however, although some of the caterpillars 

 were found in the neighbouring gardens, there does not seem much probability of ulti- 

 mate success, for, even in Cambridgeshire, they are confined to the fens, and abound 

 only where there is sedge. I am inclined to think that sparrows and other birds would 

 alone effectually stop their increase. I am aware that many naturalists will be much 



