ENTOMOLOGY IN OUTLINE HEMIPTERA. 



49 



where these organs are commonly filiform and somewhat thickened at 

 the tip. There are two principal types of legs in this division, although 

 these are variously modified for particular modes of life, the one being 

 adapted for crawling, the other for leaping. The former have short 

 legs, generally stout; the latter have the hind legs long, often curved 

 and set with rows of stiff spines." 



Family Cieadidse. This includes the harvest-flies, seventeen-year 

 locusts, etc. These insects are of large size, and are generally well 

 known. This family 

 lias a peculiarity 

 found in no other 

 member of the Hem- 

 iptera: the possession 

 of a musical appara- 

 tus. The song of the 

 cicada is well known, 

 and is produced by 

 special organs con- 

 sisting of two large 

 parchment sacs. The 

 surfaces are ribbed 

 and, when in action, 

 the air is forced 

 against these ribbed 

 surfaces, producing 

 sound vibrations and 

 forming the song. It- 

 is probable that this 



'song" is used for the 



FIG. 47. Periodical cicada (C. septendecim). a, pupa, ready to 

 change; 6. pupa skin from which the adult (c) has 

 emerged : e. eggs taken from the egg-punctures (d). 



purpose of attracting 



the female, as these organs are found in the male only. This fact was 



known to the ancients and an old Greek, Xenarchos, says: 



"Happy the cicadas' lives. 

 For they all have voiceless wives." 



The females deposit their eggs in slits which they make in the twigs 

 of trees; these eggs hatch in about six weeks and the young drop to the 

 ground and bury themselves in the earth, where they are supposed to 

 attach themselves to the roots of trees and shrubs, and where they 

 remain until they reach their mature stage, when they force their way 

 from the earth and attach themselves to any convenient object. Here 

 the back of the pupa skin splits and the mature insect, fully winged, 

 creeps forth. It requires some little time for its wings to fully develop, 

 when the newly hatched cicada takes flight to start a new cycle. 

 4 E 



