OTHER INSECTS 165 



and the anus. Count the number of somites, comparing with the 

 adult of the same species. Draw such a larva (X 3 or 4) from a 

 lateral view, showing these parts. 



Exercise 2. — The Wasps and Ants. 



(c) "Wasps of the Genus Polistes are very common and are easily 

 collected when they enter unscreened buildings with the approach of 

 cooler weather in the fall. Head, thorax, and abdomen will again be 

 recognized as in the other insects. How many somites in each? Look 

 for antennse, compound eyes, ocelli, mouthparts, and anus. At the 

 posterior end of the female is the sting. The spiracles are a row of 

 minute dots on each side of the abdomen. Compare the divisions of 

 the thorax and of each of the legs with the corresponding parts of the 

 grasshopper. To which somites are the wings attached? Draw a side 

 view (X 3 or 4) , with wings spread dorsally. 



(d) Examine the "paper" nests of this wasp and others, if avail- 

 able. Observe artificial ants' nests and the eggs and larvae recently 

 taken from an ant colony. The most interesting facts regarding the 

 ants, bees, and wasps are those connected with their social life in such 

 colonies. It is possible to observe many of their activities in colonies 

 kept in the laboratory in finely screened or glass-covered cages. 



Exercise 3. — The Butterflies and Moths. 



(e) Examine a good-sized butterfly, or moth, going over the fea- 

 tures noted for other forms : the three main divisions of the body, eyes, 

 antennse, mouthparts, legs, and wings (c/. Figs. 72 and 73). Mount 

 some of the "dust" from the wing surface and examine under a micro- 

 scope. The scales observed are a modification of the hairlike processes 

 seen on the bodies of many insects. Draw the entire animal from a 

 dorsal view, with wings spread, making the figure about 10 cm. across ; 

 omit the color pattern. 



(f) If available, the eggs of butterflies or moths will be shown as a 

 demonstration. Understand to what species such eggs belong and 

 where they are laid (c/. Fig. 73 c). 



(g) Examine such larvae, or caterpillars, as may be available. 

 Where are the head, thorax, and abdomen? Do you find thoracic legs? 

 There are paired structures on the abdomen which are not true append- 

 ages and which are known as prolegs. How many are there, and 

 what is their structure as compared with the thoracic legs? Are there 

 compound eyes, ocelli, antennse, and mouthparts as in other forms? 

 Do you find spiracles? Draw a side view on a large scale. 



(h) During the proper season, living specimens of the larvse of va- 



