98 INSECT BEHAVIOR 



it never reaches the chrysalis state, but when the maggot host itself 

 changes into one, the apparently immature Xenos pushes one end of 

 its body out between two of the host's abdominal segments and there 

 gives birth alive to a great many tiny beetles, in the earliest and most 

 undeveloped stage of their lives. 



Owing to the position of the comb, when the young wasp emerges 

 from its egg, it is suspended head downwards in the cell. It is, how- 

 ever, attached to the cell at its posterior end and remains so until 

 full grown and ready to spin its cocoon. At this period it becomes 

 detached but the bottom of the silken cocoon, which has now been 

 spun, forms a capstone to the previously open cell and prevents the 

 youngster from tumbling out. In this position the young wasp trans- 

 forms to the pupal state, in which it remains for some time before 

 issuing as a perfect insect to take up the work of the colony. 



After this event the cell is thoroughly cleaned out by the workers 

 and used over again by the queen. The entire period from the time 

 that the egg is laid until the full grown wasp issues from its cocoon, 

 is about five weeks; thus it will be seen that the same cells may be 

 used several times during a single season. 



The last brood of the year consists mostly of queens and drones 

 and after these have been hatched the workers of the colony soon 

 die. The inside of the cells may then be found to contain curious 

 brownish skins, cast off by the chrysalids and which the workers did 

 not have time to remove before the cold weather arrived. 



Unlike the large globular nests of the hornets, those of the paper 

 wasps are simply a mass of uncovered cells, ranging in numbers from 

 fifty to three hundred. These are suspended by a single central stem 

 from the undersides of large overhanging stones or from beams in 

 old barns and sheds. 



These insects are undoubtedly beneficial from the fact that they 



