THE DOMINANT INSECT 11 



vigorous and assertive insects have become almost cosmo- 

 politan in their range. Among these is the familiar 

 painted lady butterfly which is found in all quarters of 

 the globe, with the exception of South America, where 

 its place is taken by a closely allied species. The tiny 

 codlin moth — a well-known " pest " — occurs wherever the 

 apple is cultivated ; while certain beetles, such as the 

 grain weevil, the mealworm and the bacon beetle, work 

 mischief in the storehouses and barns of mankind in every 

 clime. The North American monarch butterfly migrates 

 annually in vast swarms to Canada, and presses northward 

 until it is stopped by the cold. Within the memory of 

 man it has extended its range over the whole of the 

 Pacific Islands, while competent observers believe that, 

 ere many years have passed, it will become firmly estab- 

 lished on the Asiatic continent. Should this happen, the 

 invasion by this insect of all the warmer parts of Asia and 

 Europe, and the whole of Africa, can only be a question 

 of time. In this way have insects contrived to get about 

 in the world. 



The range of size covered by insects, although at first 

 less obvious, is scarcely less remarkable than their geo- 

 graphical distribution. A West African Goliath beetle, 

 side by side with our own " seven-spot " ladybird, affords 

 a striking comparison. Yet the ladybird is not, strictly 

 speaking, a very small insect. A family of beetles to 

 which naturalists have given the ponderous name of 

 TricJiopterygidce comprises many species which could 

 crawl easily through the eye of a small needle. Again, 

 there is a Brazilian moth with a wing expanse of more 

 than eleven inches from tip to tip ; while at the other end 

 of the scale we find moths so small that their beauties — 

 one might almost add their very existence — can only be 

 perceived by the aid of the microscope. According to Sir 



