APPENDIX. 497 



during the day, and will be in perfect condition.] If left to them- 

 selves they will again fly for a short time after sunset. Out-of- 

 doors the moths are very rarely seen, though they must be abundant 

 enough some years in early autumn. I have only once taken D. 

 nerii at flowers, though I have on a few occasions found them in 

 the daytime resting on palings or bushes. Dr. Sie'pi has taken them 

 in September, flying round petunias at Marseilles, but never com- 

 monly. I may say that most of the tacts I have been able to obtain 

 concerning D. nerii lend strength to the theory that it is not a true 

 native of southern France, but a species renewed here entirely each 

 year by immigration. All late pupae make an attempt to mature the 

 moth during winter, but without success out-of-doors after about 

 November 15th. I have never known one to pass the winter and 

 hatch : n the spring, and, therefore, it is pretty certain that D. nerii 

 does not hybernate as a pupa. I have found no larvae nor ova in 

 winter or spring, my earliest date for the larva being July 12th (it is 

 true that those captured were nearly fullfed at this date, but they are 

 rapid growers and had probably left the ova not earlier than the 

 middle ot June). As to the possibility that the perfect insect 

 may hybernate, I have not proved that it does not do so, 

 but I have never come across one either in winter or spring, 

 nor do I know of any record of I). nerii in spring in southern 

 France. A few specimens, bred in November, which I kept out- 

 of-doors in a large cage containing some foodplant, died in about a 

 fortnight, and, apparently, no pairing took place. No eggs were laid, 

 and two females which I dissected had no trace of eggs in their 

 bodies. I feel compelled, therefore, to consider those specimens, 

 which have been reported as occurring here in June, immigrants. Many 

 more must in some years arrive later in the summer. It is reasonable 

 to suppose, however, that many of the September and October larvae 

 are the offspring of moths that have emerged here in the summer, 

 and not first descendants of the immigrants. I often wonder where 

 these travellers come from — possibly from southern Italy, Algeria or 

 Greece. It appears that I), nerii is abundant in Asia Minor, 

 and is, no doubt, firmly established there, but it is hard to 

 believe that our stock is kept up from such a distance. The 

 moth is a powerful flier, but its flight is of short duration, 

 restricted to half-an-hour or less at dawn and after sunset. One 

 is tempted to ask whether, when migrating, it keeps on the wing 

 all night or comes on by short stages at dawn and dusk. If it 

 crosses the sea it must be on the wing for a fairly long time. The 

 larvae occasionally found in central Europe, which certainly must come 

 from immigrants, and the moths sometimes met with in England 

 and northern Europe, prove pretty conclusively the migratory 

 habits of this species. It would be interesting to find out 

 whether more specimens have been recorded in the north in those 

 years in which D. nerii has been specially abundant here in the south, 

 e.g., 1899, 1900 and 1903 were years of abundance at Hyeres, 1901 

 and 1902 years of scarcity (Powell). 



[Page 259. J Time of appearance. — My earliest moths emerged 

 between August 3rd and 9th, 1900, from pupae formed about July 20th. 

 Here are a few other dates : — 1899 : earliest September 13 h, 18th, 

 20th, 22nd, latest mid-November. 1900 : September 20th to 



