174 



BOYS AND GIRLS IN BIOLOGY. 



men are again divided, as the lobster's, into body-pieces 

 — somites. All insects have three pieces, or somites, in 

 the breast, or thorax, but all do not have the same 

 number of pieces (somites) in the abdomen. Some 

 have eleven, others not so many. At the top of the 

 butterfly's head you will see two great compound eyes 

 (Figs. 141, 142), all divided into six-sided squares ; each 



Fig. 141. 



square, you know, is a separate eye, and some butterflies 

 have more than thirty thousand in both eyes ! These 

 compound eyes are not set on stalks, as the lobster's. 

 Next we come to the butterfly's curious mouth.. Two 

 horny scales at the sides of the mouth are all that are 

 left of the lobster's large mandibles or the caterpillar's 

 jaws. Behind the mouth you will see something like the 

 lobster's lip (labrum), a small scale with two long palps 

 (Fig. 142). We find the mouth itself all coiled up un- 



