38 



INSECTS INJURIOUS TO THE APPLE. 



exactly })erpendicular, and these are firmly cemented and 

 varnished so as to be water-tight. As the insect progresses, 

 the chamber is filled below by the earthy matter removed in 

 its progress, but the upper portion, to the extent of six or 



eight inches, is empty, 

 Fig. 26. and serves as a dwell- 



ing-place for the insect 

 until the period for its 

 exit arrives. Here it 

 remains for some days, 

 ascending to the top of 

 the hole in fine weather 

 for warmth and air, and 

 occasionally looking out 

 as if to reconnoitre, but 

 descendino; again on the 

 occurrence of cold or 

 wet weather. In locali- 

 ties that are low or im- 

 perfectly drained, the insects sometimes continue their galleries 

 from four to six inches above ground, as shown in Fig. 26, 

 leaving a place of egress at the surface, e, and in the upper 

 end of these dry chambers the pupae patiently await the time 

 for their next change. 



This period, although an active one, is the pupal stage of 

 the insects' existence, and finally, when fully matured, they 

 issue from the ground (see a, Fig. 24), crawl up the trunk 

 of a tree or any other object to which tiiey can attach them- 

 selves securely by their claws, and, having rested awhile, 

 prepare to cast their skins. After some struggling, a longi- 

 tudinal rent is made on the back, and through this the en- 

 closed cicada pushes its head, and then gradually withdraws 

 itself, leaving the empty pupa skin adhering, as shown at b in 

 Fig. 24. The escape from the pupa usually occurs between six 

 and nine in the evening, and about ten minutes are occupied 

 by the insect in entirely freeing itself from the enclosure. At 



