OTHER MEMBERS OF THE CLASS — INSECTA 175 



Squash bug, scale insects, cicadas, etc. — The order, 

 Hemiptera, is a very large one containing besides the ones 

 named, a host of others, as the water boatmen, back 

 swimmers, stinkbugs, 

 etc., that are known 

 as the " bugs." The 

 mouth parts are formed 

 for sucking and the 

 metamorphosis is in- 

 complete. Those that 

 possess wings have 

 two pairs. Most of the 

 members of the order 

 have the basal half of 

 the front wings thick- 

 ened, but the others 

 have the front wings 

 thin throughout their 

 whole length. Most 

 people call an}' insect „ ,,. „,,, - , ,a 



^ ' ■' Fig. 115. — Head of a dog-day harvest fly, en- 



abug; but entomolo- larged to show mouth parts : Mrf, mandibles; 

 ffists restrict the term ^^' "^^''i"*; "S; sheath, formed by the lower 

 lip, in which the four bristles are carried. 



to insects like those 



mentioned in this paragraph. Unlike the locusts, the 

 bugs have sucking mouth parts. The mandibles and 

 maxillfe have grown out into long, slender, bristlelike 

 organs. These four bristles are inclosed in a segmented 

 sheath formed by the lower lip (Fig. 115). The bristles 

 and sheath together form a " bill," or " beak," as it is 

 called. This beak is plainly seen on the ventral side of 

 the thorax, between the bases of the legs, in a squash bug, 

 harlequin cabbage bug or dog-day harvest fly. With care 



