424 NATURE STUDY AND LIFE 



passing from the egg to the adult and that live by suck- 

 ing the juices of plants or animals. They stand low in 

 the scale of insect life. 



The children will doubtless have brought in, for worms 

 or insects, a number of forms that do not fit in any of the 

 above groups. They are probably wormlike but have far 

 too many legs to be classed with the insects or spiders. 

 If not garden slugs, which will be described under the 

 head of mollusks, they are probably either centipedes 

 (hundred legs), millipedes (thousand legs), or " sow bugs." 

 These are figured above, and when we speak of them here- 

 after we shall call them by their right names and not call 

 them insects, worms, or bugs. 



The centipedes live in damp places, under logs and 

 stones, and feed on insects. The millipedes live in simi- 

 lar places and eat decaying vegetable matter principally, 

 but sometimes living plants. They may become a serious 

 pest in a strawberry bed by eating holes in the ripest 

 berries. The sow bugs are often found in great numbers 

 under rotting boards and logs. They undoubtedly find 

 plenty to eat, but to discover just what it is we shall have 

 to make feeding tests. Sow bugs belong to the great 

 group of Crustacea along with the crayfishes and crabs. 



Earthworms. — Every boy has made the acquaintance of 

 these animals as bait for a fishhook, but how many know 

 or realize the role they play in nature.' Says Darwin^: 



When we behold a wide, turf-covered expanse, we should remem- 

 ber that its smoothness, on which so much of its beauty depends, is 

 mainly due to all the inequalities having been slowly levelled by 

 worms. It is a marvellous reflection that the whole of the superficial 



1 Vegetable Mould and Earth- Worms ^ p. 313. 



