46 



Marvels of Insect Life. 



Campodea has false legs on the hind-body like the silver-fish, but here they are 

 more numerous, there being five pairs, situated on the second to the seventh rings of 

 the hind-body. The breathing system is very elementary. There are only six air- 

 openings, or spiracles, three on each side of the fore-body, and each of these, instead 

 of opening into one general system of air-tubes, has a separate unconnected system 

 of its own. Not many years ago this Insect was invested with a great amount of 

 interest for naturalists, because it was contended that it represented the primitive tvpe 

 from which in all probability the entire race of Insects have descended. That view 

 is not held at the present dav. 



Butterfly Swarms. 

 Almost from our infancy we have all been made familiar with the fact that devas- 

 tating swarms of locusts periodic- 

 ally fly from land to land, especially 

 in the East, not only destroving as 

 they go, but leaving behind them 

 the seeds of famine in the shape 

 of countless eggs that produce 

 the far more destructive nymphs. 

 But locusts are not the only 

 Insects that migrate from place 

 to place in millions. Many birds, 

 we all know, perform these asso- 

 ciated movements twice a year 

 over enormous distances ; but it 

 is not so well known that certain 

 species of butterflies with their 

 fragile wings frequently under- 

 take similar flights, during which 

 they cross seas and battle with 

 adverse winds. From the small- 

 ness and fragility of a butterfl\'s 

 bod^' as compared with the 

 enormous expanse of wings, it 

 appears to be quite imsuited to 

 such an enterprise ; and yet the 

 fact remains that it is a successful 

 migrant. Our home-grown stock of 

 the large garden white is frequently 

 reinforced by great immigration from the Continent. A large percentage of the yellow 

 and black caterpillars that have skeletonized our cabbages never produce butterflies 

 because they are killed off by internal parasites ; and it is not improbable that 

 the large white ^ might cease to be a British species were these migrations to cease. 

 Clouds of these butterflies have been observed passing across Europe from north-east 

 to south-west, and have been met with half-way across the English Channel. Darwin 

 mentions a flight of another species observed by himself and Captain iMtzroy from 



1 Pit-ris brassica!. 



Photo by] 



[H. Bastin. 



A Group of Fire-brats. 



A Small company of these remarkable little Insects is here shown on a larger 

 e.xhibiting the under as well as the upper side. 



scale 



