president’s address. 
150 
seen. A thunder-storm with high winds subsequently put 
an end to the migration. These little creatures, i.e., the 
Gamma Moths, follow an east to west migration, and they 
adhere to it with as much steadiness and precision as the 
different migratory hosts of birds which are observed here. 
That they accomplish their journey in safety is shown by 
the enormous swarms of them which frequently cover the 
east coast of England, and which can only be explained as 
the result of immigration. This species seems to extend 
over the whole of the northern half of the globe, but does not 
appear to have crossed the equator, unless some specimens 
recently taken by the Rev. A. Miles Moss, in Peru, should 
prove to be P. gamma. 
The Painted Lady ( Cynthia cardui) is even more cosmopol- 
itan than the gamma Moth, being found all over the world, 
with the exception of the Polar Regions and South America. 
I have even received it from so remote an island as Norfolk 
Island, midway between Australia and New Zealand. 
Enormous migrations of this species have frequently been 
observed. Several of the Hawk Moths, which are insects 
of very powerful flight, are very widely distributed over the 
surface of the globe, as for instance Chaerocampa celerio, the 
sharp-winged Hawk Moth, and Deilephila livornica, which are 
spread all over Europe, Asia, Australia and North America ; 
and the Death’s Head Moth, Acherontia atropos, which is 
found all over Europe, Africa, and Asia : but does not seem 
to have reached Australia or America. We must not, how- 
ever, suppose that either the power of flight or the tendency 
to migrate necessarily determines the distribution of any 
particular species, as there are some Hawk Moths whose 
powers of flight are equal to those of celerio and livornica, 
but whose distribution is very limited. Probably in these 
cases, the restriction of the larvae to certain food plants may 
account for their not being widely spread. As instances of 
insects in whom the migratory tendency is well developed, 
