394 



so that the moths themselves are bom iu the water, and these last 

 have even the faculty of entering the water in their perfect state, 

 having been seen to " creep down a pond-weed stem for an inch or 

 two, emerging again with vmwetted wings." * 



And then to pass to other questions of more general import. 

 What is the relation of insects to the particular spots in which they 

 are found livingl What are the causes which operate in the 

 general distribution of insects 1 Very many species seem to 

 migrate instinctively at certain seasons, and if carried by storms 

 and adverse winds beyond their mark may easily make their 

 appearance in countries in which they had not been seen before. 

 Many travellers and voyagers testify to having witnessed, on dif- 

 ferent occasions, countless myriads of butterflies, as well as of other 

 insects, all traversing the air in one direction, the passage of the 

 whole body occupying several hours. The migrations of the locust 

 tribe in the East are notorious. Even in our own country, towards 

 the end of summer, we may often observe large flights of aphides, 

 winged ants, and occasionally insects belonging to other orders, 

 when they have increased beyond their usual numbers, quitting 

 their homes and seeking spots whei-e they may found new colonies. 

 Indeed all insects that are in the habit of taking wing, without any 

 intention of migrating, are liable to be transported by sudden gusts 

 to regions far distant from the places where they were bred, or to 

 be carried out to sea and borne upon " floating timber and other 

 drift materials " to entirely a different quarter of the globe.t 



It is perhaps to migration that we are to attribute the circum- 

 stance of the appearance in this countiy, some years in considerable 

 abundance, of certain species of butterfly well known on the Con- 

 tinent, but of which in other years no specimens are to be seen here 

 even for several seasons in succession. Such has been the case this 

 last autumn with the Va7iessa antiopa, or Camberwell beauty ; which 

 " appeared in scattered localities all over the country, the capture 

 of upwards of 200 specimens " having been recorded in diff"erent 

 places " from the Channel Islands to Aberdeen." This is usually 



* Ent. Trans., 1872, pp. 134 and 138. 



t See a Paper on the "Dispersal of Insects," by Albert Miillcr, Trans. Ent. 



Soc, 1871, p. 175. 



