134 THE ENTOMOLOGIST. 



what kind of Callidryas it was. This was probably Catopsilia 

 fiorella, stated by Trimen not to be common, but now swarming 

 everywhere. Again, Trimen saw only one specimen of Danais 

 chrysippus. This species is also now common everywhere. 



Of other species mentioned by Trimen, Atclla phalanta is 

 so numerous in certain places that I have caught two at a time 

 in my net. Pyrameis cardiu was not seen, but is now common. 

 Neptis frohenia has increased in numbers, and so also must 

 Hypolimnas misippus, since Trimen only saw one specimen of 

 this butterfly. He also only found L. boetica and L. telicamis, 

 and what he thought was L. lysimon. I found L. boetica, L. teli- 

 canus, Z. gaika, and Z. knysna all common almost everywhere. 

 So we find that in 1833 there were 21 species of butterflies 

 observed in the island ; in 1865, 26 species ; in 1899, 28 or 29 

 species ; in 1907, 32 species at least are reported. How the 

 butterflies arrive in Mauritius is a matter of conjecture. The 

 nearest large expanse of land is Madagascar, 550 miles distant. 

 Once, however, a species reaches the island various causes allow 

 it to remain and multiply. One is the absence of " collectors" 

 to harry and decimate it. The extraordinary variety and luxuri- 

 ance of the vegetation of the island permit the incoming insect 

 to either at once find its natural food-plant or some allied one, 

 which will do just as well. 



At Port Louis I found the larvfe of Daphnis nerii feeding on 

 oleanders, and took them up to Curepipe, 1600 feet above sea- 

 level, where no oleanders grow. The curator of the Curepipe 

 Botanical Gardens, however, showed me an allied tree growing 

 in the jungle, and on this the nerii larvae fed up readily. I sub- 

 sequently found these larvae on half a dozen different kinds of 

 shrubs. The larvae of Acherontia atropos feeds on at least a dozen 

 different kinds of trees and plants all over the island ; conse- 

 quently it swarms in the island. Then, again, climatic conditions, 

 and the varying temperature between Port Louis at sea-level 

 and Curepipe at 1600 feet, allow a continuous succession of 

 broods to be produced. I have often found eggs, larvae of diffe- 

 rent sizes, pupae, and imagines of Papilio phorbanta on the same 

 day. 



Yet another reason for the increase seems to be the want of 

 ichneumon-flies and other parasites. I bred nearly all the 

 Mauritius butterflies from larvae, and also dozens of hawk-moths, 

 including D. nerii and A. atropos, and I do not remember to have 

 had a single caterpillar or pupa infested with ichneumons. 



Against these reasons for increase, however, should be placed 

 the enormous damage that must be done to insect life by the 

 violent cyclones that annually visit the island with more or less 

 intensity. In December, 1900, whilst I was in the island, a very 

 violent cyclone that lasted for three days arrived. So violent 

 was the wind that all the leaves were torn off the trees, so that 



