182 



BOYS AND GIRLS IN BIOLOGY. 



that the beautiful butterfly is very much like the fierce, 

 odd-looking lobster. Let us first notice the general 

 shape of their bodies ; both are long, rounded, and ta- 

 pering at each end, with joints, or appendages, hanging 

 down each side. The body of each is divided into 

 three parts — the head, thorax, and abdomen ; and 

 these are made up of different pieces called somites. 

 The somites have a back or tergal portion, a side, or 

 pleuron, and a lower or sternal portion. The butter- 

 fly's wing corresponds to the pleuron, or side-piece, of 

 the somite which covers the gills. There is also a great 

 likeness between the appendages of the two animals. 

 Both have compound eyes at the front of the head ; the 

 main difference between the eyes is, that the lobster's 

 are placed on movable stalks, while the butterfly's are 

 sessile, that is, they are set in his head without stalks. 

 The lobster has one more pair of feelers than the but- 

 terfly, and the butterfly's feelers answer to the second 

 pair, or the antennules, of the lobster. There looks to 

 be no resemblance between the mouth of the lobster and 

 that of the butterfly, yet there is a close likeness. The 

 scale with two long palps takes the place of the lob- 

 ster's labrtjm. The horny scales at 'the sides are the 

 lobster's jaws, or mandibles, made butterfly-fashion ; 

 and the two strong maxilla, or little jaws, of the lob- 

 ster are worked over into the two long, fine half -tubes 



