66 THYSANURA. 



Standard Natural History, p. 137, Fig. 200). Be- 

 sides these there are two long, caudal setae {se) at the 

 end of the abdomen, which are so similar in structure 

 to the antennae that it seems as if they must perform 

 a similar function. Many of the hairs near the abdom- 

 inal appendages, and on the base of the setae, look 

 like deeply cleft leaves, and others are forked at their 

 ends. The appendages at the end of the abdomen 

 have given the name Thysanura (^vWvos, a tassel ; 

 ovpa, the tail) to the order, and the members of the 

 family Campodeae and Lepismatidae are known as 

 Bristle-tails, in distinction to the Poduridae or Spring- 

 tails. The latter are small Thysanuran insects that 

 are abundant in wet places. One genus (^Achoreutes 

 nivicola) often occurs on snow, and teachers may 

 sometimes have a plate of snow brought in to them 

 covered with these tiny leapers. 



According to Meinert ^ there are three pairs of 

 spiracles in the thorax of Campodea, one pair in each 

 ring, and none in the abdomen, 



LEPISMATID.E, 



Lepisf?ia saccharina (Fig. 28, f ) is often found in the 

 attics of houses, about old wdndow-casings, and under 

 loosened wall-paper. It is large enough to be studied 

 with a common magnifier, and can be used to better 

 advantage in the schoolroom than Campodea. The 

 body is covered with scales which resemble those of 

 the Lepidoptera, and give a silvery appearance to the 

 insect. When examined microscopically, they are 



1 Ann. Mag. Nat. Hist., 3d ser., Vol. XX., 1867. 



