SOME INSECTS INJURIOUS TO ORCHARD FRUITS 551 



fifteenth and sixteenth years great numbers of the pupae may be 

 found near the surface, and a few individuals may emerge during 

 May and June of the sixteenth year. Early in April of the seven- 

 teenth year the pupae commence to make preparations to emerge 

 from the ground by excavating burrows or exit galleries to the 

 surface. These exits are completed by the last of April. Ordi- 

 narily they extend only to the surface, and are kept open from a 

 depth of a few inches to a foot or more. In some soils these 

 exit holes are extended four or five inches above the surface by 

 means of clay carried up from the subsoil, and are called cicada 



FIG. 402. Pupal galleries or chimneys of the periodical cicada: a, front 

 view; e, orifice; 6, section of a; c, pupa awaiting time of change; d, 

 pupa ready to transform reduced in size. (After Riley, U.S. Dept. Agr.) 



chimneys. The pupae come from the ground in the evening and at 

 night, usually between sundown and ten o'clock, and proceed to 

 the nearest upright object, which may be a tree, the side of a 

 building, fence, or weed stem anything, in fact, upon which they 

 can climb and expose their bodies to the action -of the open air. 

 In about an hour after emerging the skin on the back splits open 

 and the adult insect works its way out (Fig. 403). The wings, 

 which are short and soft at first, rapidly develop; the body, 

 wings and legs harden, and by the following day the adult is ready 

 to take flight and enter upon its short aerial life, limited to about 

 thirty days. During this short period they feed but little, if at 



