Marvels of Insect Life. 



Ring-like Structure. 



A diagram representing a few 

 segments of an Insect's body. 

 The thick portions of outline 

 indicate the harder parts, 

 which thin away into the 

 supple, inward folds, which 

 allow the hard rings free play. 

 The thin lines connecting tlie 

 hard and soft parts represent 

 the muscles which move the 

 several parts. 



The Insect Heart 



A small portion only of the " dorsal vessel " 

 of a beetle is here shown. The coimected 

 chambers of w-hich it consists expand and con- 

 tract in rotation, and the free blood is drawn 

 in at the valvular openings and discharged 

 from the fore-part of the vessel, whence it finds 

 its way to all parts of the body and limbs. 



consists of animals to which 

 these authorities ha\e cjiveii 

 the name of Artlu'opods. It 

 inchicles the crabs and lobsters, 

 spiders, centipedes. Insects, etc. 

 All these creatures agree in 

 having the bod\' built in seg- 

 ments or rings, all or some 

 of which bear jointed append- 

 ages. The Insects differ from 

 the others in having these 

 segments grouped, in adult life, 

 into three regions, usually 

 fpiite distinct. These regions 

 are the head, the fore-body, 

 and the hind - body. The 

 spiders, which are commonly- 

 regarded in popular esti- 

 mation as Insects, have only 

 two body-regions. There are 

 other differences, of course, 

 which are not evident upon a 

 superficial view of the exterior 

 form ; but e\en here two or 

 three additional points may be 

 mentioned, contrasting a spider 

 with an Insect. The 

 head of the Insect 

 bears a pair of an- 

 tenna:^, or " feelers " ; 

 the spider has no 

 antennae. The Insect, 

 with a few excep- 

 tions among the 

 simpler forms, has a 

 pair of prominent 

 compovmd eyes made 

 up of a large num- 

 ber of lenses, and 

 two or three simple 

 e\'es, or " ocelli," 

 placed between the 

 compound e3^es. The 

 spider's eyes are ail 

 simple, and nuinlier 



The Nerves of an Insect. 



Hi're is shown the nervous system of a gad-fly. 

 The central trunk line is enlarged into 

 knots or nerve centres at intervals, from which 

 finer nerve threads extend to the extremities 

 of th':' limbs and to every part of the body. 



An Insect's Digestive System. 



The body of a bee is here laid open from above 

 to show the digestive system. .M the upper 

 part of the diagram its beginning is shown in 

 the extended mouth parts passing back into the 

 gullet w-ith its terminal enlargement, the crop 

 or stomach, and ending with the intestines. 

 The ner\ous and circniatorv systems are here 

 turned aside to the right and left respectively. 



