SECOND WEEK. 



NKEDED. A number of grasshoppers. 



FIRST HOUR. Examine the front wing, noticing the strong vein 

 extending to the base (subcostal vein) , and also the other strong vein 

 (median vein), which, with the subcostal vein, divides the wing into 

 three more or less equal parts. Notice further the costal vein, inde- 

 pendent vein, and submedian vein within these areas. Draw an out- 

 line of the wing, naming these parts costal, median, and internal 

 areas, and sketch in roughly the veins and their branches. Now on a 

 larger scale draw the base of the wing, indicating accurately the num- 

 ber and origin of each vein in this region. 



SECOND HOUR. Draw one of the hind wings in the same way as 

 directed above for the front wings, marking out very carefully the ho- 

 mology of the veins with those of the front wings. 



THIRD HOUR. The three segments of the thorax are called the 

 pro- meso- and metathorax,and the same prefixes are used to designate 

 the parts of each of these segments. Above they are called tergum or 

 notum, the sides plurae, and beneath sternum. The notum is divided 

 into four tergites (praescutum, scutum, scutellum, and postscutellum), 

 the pleurae into twopleurites (episternum and epimeron), and the ster- 

 num of each segment contains but a single sternite. Describe or draw 

 these parts as they appear on the grasshopper, noting particularly: (a) 

 The great size of the pronotum, () the absence of the praeepimeron, (<:) 

 the small size of the prosternum, and (d) the dovetailing between the 

 sternites of the second and third thoracic and first abdominal segments. 



