52 STUDIES OF ANIMAL TYPES 



Make a drawing of a front wing and a hind wing. 



Detach a front leg. Note that it is composed of segments 

 of unequal length. The first one is called the coxa. It is 

 short and globular. The second segment is the trochanter, 

 the third femur, fourth tibia, and the remaining ones are 

 called the tarsal segments. The last tarsal segment bears 

 a pair of claws. 



Make a drawing of a leg. 



Abdomen. Note that between the segments is soft, 

 flexible skin, which furnishes freedom for movement. Note 

 that the skin of the segments is hard and smooth. This is 

 due to a hard horny substance called chitin that is deposited 

 in the skin. On each side of the first segment is an oval 

 transparent membrane that constitutes the ear of the insect. 



On each side of each segment, near the front margin, will 

 be seen a small aperture. These are the openings, termed 

 spiracles, through which the insect takes in air. 



The last segments bear in the female two pairs of strong 

 curved organs. These compose the ovipositor. They are 

 used to make holes in the ground in which to lay the eggs. 

 The end of the abdomen of the male is blunt and rounded, 

 and bears three inconspicuous appendages. 



D. INTERNAL FEATURES. With head directed from you, 

 pin a freshly killed female locust on its ventral surface in a 

 dissecting pan, by spreading the wings and pinning them 

 securely to -the wax or cork. Run a pin through the 

 posterior end of the abdomen into the cork. With a pair 

 of scissors cut carefully, from the ovipositor to the head, 

 just through the skin, on the dorsal side, a little to the left 

 of a median line. With a forceps lift away the skin on the 

 right of the slit and note the delicate, whitish blood vessel, 

 the heart. Where does the heart lie? How long is it? 



