34 THE bbe-kbbpbr's guidb ; 



usually without appendages, contains the ovipositor, and, 

 when present, the sting. Insects undergo a more striking 

 metamorphosis than do most other animals. When first 

 hatched they are worm-like, and called "larvze " (Fig. 39,/), 

 which means masked; afterward they are frequently quies- 

 cent, and would hardly be supposed to be animals at all. They 

 are then known as pups (Fig. 39, ^). At last there comes forth 

 the mature insect or imago (Fig. 1), with compound eyes, 

 antennae and wings. In some insects the transformations are 

 said to be incomplete, that is, the larva, pupa, and imago differ 

 little except in size, and that the latter possesses wings. The 

 larvas and pup^e of such insects are known as nymphs. We see 

 in our bugs, lice, locusts and grasshoppers, illustrations of 

 insects with incomplete transformations. In such cases there 

 is a marked resemblance from the newly-hatched larva to the 

 adult. 



The other classes of the phylum Arthropoda, are the Crus- 

 tacea, Myriapoda, and Arachnoidea. The Crustaceans include 

 the jolly cray-fish and the lobster, so indifferent as to whether 

 they move forward, backward or sidewise ; the shorter crab, the 

 sow-bug, lively and plump, even in its dark, damp home under 

 old boards ; and the barnacles, which fasten to the bottom of 

 ships, so that vessels are often freighted with life, without, as 

 well as within. 



The myropods are the so-called "Thousand-Legged Worms. ' ' 

 These are wormlike in form. The body is hardly differentiated 

 at all. The name comes from the numerous legs, which 

 though never a thousand may reach one-fourth that number. 

 Myriapods have only simple eyes, and all have antennK. Of 

 the Myriapoda the Millipeds have numerous segments, often 

 as many as sixty, have four legs to each joint, are cylindrical, 

 and are often pests in the garden, as they are vegetable eaters. 

 The Centipeds have fewer joints, may be no more than thirty, 

 only one pair of legs to each segment, and feed on insects, etc. 

 Their bite is venomous, and the bite of the larger ones may 

 prove harmful even to man himself. 



The Class Arachnida includes the spider group. These 

 animals all have, when mature, eight legs. They never have 

 but two parts to the body, the head-thorax and abdomen. 



