386 THE ZOOLOGIST. 



three were remarkably tender, and good eating. — H. Holmes (Aline Lodge, 

 Stornoway, N.B.) 



MOLLTJSCA. 



Hibernation of Limax flavus.— The little yellowish coloured Slug 

 known to conchologists as Limax flavus is in the habit of hibernating in 

 small colonies. I am told by a gardening friend that he found no less than 

 twenty-four of them congregated together in a hole in a clod of earth. This 

 is a most unusual number, so far as my experience goes. — Robert Service 

 (Maxwelltown, Dumfries). 



INSECTS. 



Insect Migration. — I have read with much interest the paper on 

 migrating butterflies and dragonflies. There are several points in it 

 which appear of great interest; thus some of the authorities quoted by 

 you mention having seen swarms of butterflies sipping at damp places, and 

 on this point I can certainly confirm them. In a dark African forest-path, 

 and also in Madagascar woods, one of the most familiar sights is a great 

 assemblage of bright blue and white butterflies, taking long, deep draughts 

 of moisture from the unpleasant looking mud in a hollow of the road. 

 Still, this is just what one would expect, for I found that, at any rate in the 

 drier hours of the day, the best place for butterfly-hunting is always in the 

 vicinity of a stream, which is only natural, for every creature is thirsty in 

 Africa at such a time. With regard to their actual migration in large 

 flocks, I have never seen such a phenomenon myself; all that I can say 

 on the subject is that the sight of butterflies flying past by twos and 

 threes is common when one is on a steamer near the shore. I am 

 surprised at such an explanation as that given for these migrations, 

 because I have always understood that the life of a butterfly is a short 

 one, and how these insects should have time to migrate seems to me 

 curious. You will, of course, know that there are certain species of 

 Argynnis confined to the mountain-tops (above 10,000 ft.) of Kilimanjaro, 

 Kenia, Ruwenzori, and possibly Milanje. I think that their occurrence 

 and distribution would be worth your investigation, for these forms occur 

 only on these isolated and distant summits, and not, if I am rightly 

 informed, in the lower country between the hills. This would imply that 

 they were capable of flying 600 miles, but, of course, the chance of any 

 particular flight reaching a mountain at that distance is rather small. 

 (The proportion of chances, I think, would be 360 to one.) If I under* 

 stand your theory rightly, these migrations resemble the manner in which 

 the over-populated countries of Asia sent forth irregular swarms of Goths, 

 Huns, and others; and without some such explanation it is difficult to 

 understand the distribution of butterflies in islands, and on such isolated 



