178 THE BIOLOGY OF THE AOTMAL 



this segment. "What is the shape of the scutum ? 

 Of the scutellum ? Of the sternum ? JSTote the 

 wings or "wing covers." Where and how 

 are they attached ? What is their structure ? 

 Color? Shape? Size? Compare the legs with 

 those on the prothorax. 



Draw the mesothorax, showing all the parts. 



3. The metathorax. — Compare this segment in 

 shape, size, structure, etc., with the preceding 

 segments. Compare also the appendages, both 

 the legs and the wings, with the similar ap- 

 pendages on the other parts of the thorax, 

 noting especially the shape, size, texture, fold- 

 ing, venation, color of the wings, and the shape 

 and arrangement of the joints of the legs. Are 

 there any spiracles on this segment? If so, 

 where ? 



Draw the metathorax, also the appendages. 



d. The abdomen. — How is this connected to the thorax ? 

 Shape ? Size as compared with the head and the 

 thorax ? What is its structure ? Count the see:- 

 ments on the dorsal and on the ventral side. How 

 does the number on the upper side compare with 

 that on the lower? Does this region bear any 

 appendages? Examine the first segment of the 

 abdomen. Does it have both tergum and ster- 

 num ? Note the large opening, the " ear," with 

 the membrane or "drum" stretched across it. 

 How many " ears " are there ? Does this segment 

 bear a spiracle ? If so, what is its position ? Note 

 on each side of the abdomen a longitudinal fold. 

 Pull the tergal and sternal regions slightly apart. 

 Is this fold composed of a flexible membrane? 



