INSECTS 



Fig. 119. Males of the large and small form 

 of the periodical cicada (natural size) 



the eggs into the twigs of trees and bushes. Ordinarily the 

 ovipositor is kept in a sheath beneath the rear half of the 

 abdomen, but when in use it can be turned downward 

 and forward by a hinge at its base (Plate 7). The oviposi- 

 tor consists of two 

 lateral blades, and a 

 guide-rail above. The 

 blades excavate a cav- 

 ity in the wood in- 

 to which the eggs 

 are passed through 

 the space between the 

 blades. 



It was formerly sup- 

 posed that the period- 

 ical cicada takes no 

 food during the brief 

 time of its adult life, 

 but we know from the 

 observations of Mr. \Y. T. Davis, Dr. A. L. (Juaintance, 

 and others and from a study of the stomach contents made 

 by the writer that the insects do feed abundantly by 

 sucking the sap from the trees on which they live. The 

 cicada, being a 

 near relative of 

 the aphids, has 

 also, as we have 

 already noted, a 

 piercing and suck- 

 ing beak by which 

 it punctures the 

 plant tissues and 

 draws the sap up 

 to its mouth. Un- 

 like the other 



SUCkillS? insects ^ IG ' I2 °' ^ male of the periodical cicada with the 



1 ■ «■ wings spread, showing the ribbed sound-producing 



that infest plants, organs, or tympana (Tm), on the base of the abdomen 



200 



