POISONOUS INSECTS AND THEIR RELATIVES 415 



true insect is an animal possessing six legs, one pair of 

 antennae, and, in most cases, one or two pairs of wings. 

 Moreover, the body of an insect is divided into three 

 divisions, head, thorax, and abdomen. A fairly sure 

 criterion to enable us to determine whether we are dealing 

 with a true insect or with some other animal is the number 

 of legs present. If there are three pairs, we may gener- 



FIG. 142. A dragon-fly. (X 1.) 



ally be sure that we have a true insect, although young 

 mites and ticks have but six legs. 



Starting among the lower orders of insects, perhaps the 

 dragon-flies (Fig. 142), snake doctors, devil's needles or 

 spindles, as they are variously called, first demand our 

 attention. There is a prevalent idea, among children at 

 least, that these insects sew up human ears, bring dead 

 snakes to life, and perform other similar miracles. All 

 this may be dismissed with the remark that they are 

 perfectly harmless. 



The earwigs (Fig. 143) are said to have received their 

 name from the supposed habit they have of crawling into 

 people's ears. It is a curious but not easily explainable 



