COLLECTION AND PRESERVATION OF INSECTS 



29 



and fanlike. The mouth parts are formed for chewing. The nymphs 

 resemble the adults. Grasshoppers are well known for the damage 

 they do to crops, and cockroaches are among our commonest household 

 pests. (See fig. 17.) 



ISOPTERA 



Isoptera (termites, or "white ants") are small, soft-bodied insects 

 The workers are wingless. The reproductive forms have two pairs 

 of large wings with many veins. The mouth parts are formed for 

 chewing. The workers are found in colonies in wood in contact 

 with the ground. The reproductive winged forms (fig. 18) are fre- 

 quently seen swarming on warm days. These insects are frequently 

 called "white ants," but they are not true ants and may be distinguished 

 from ants by the fact that the abdomen is broadly attached to the 

 thorax. Some species are very destructive to buildings, especially 

 in warm or tropical regions. 



Figure 18. — Isoptera. The winged form of Reticulitermes flavipes (Koll.), a 

 common and destructive termite. Actual length about 10 mm. The wingless 

 workers are smaller and dull white in color. 



PLECOPTERA 



Plecoptera (stoneflies) are rather large, soft-bodied insects with 

 long legs and antennae, two pairs of large wings with not many veins, 

 and two long, taillike appendages. The mouth parts are formed for 

 chewing but are usually vestigial in the adults. The oung, or nymphal 

 stages, live in streams, and the adults are found ar streams. (See 

 fig. 19.) 



