THE SOCIAL WASPS. 34 1 



preference seems to be for the sloping under side of old roofs, eaves 

 and the protected casements of windows. Indeed, so strong has been 

 the attachment to certain sites, that I have several times seen the wasps 

 suspending one comb from another in the style of architecture charac- 

 teristic of the hornet. In New England P. paUipes builds in 

 the. open on wild rose bushes and other low shrubs, in protected re- 

 cesses of stone walls, while a tin can, a water pipe perforated by rust 

 and a sheep's skull are other nesting places which have come to my 

 notice. At Willow Grove, Pa., great numbers have made use of the 

 space enclosed by the sheet-iron water-table of a new car barn, thus 

 securing a maximum of warmth and immunity from the zealous wasp 

 hunter. In Texas, I am told, certain species build on the cacti, while 

 others prefer stone ledges; and doubtless further observation will dis- 

 close many other interesting variations in the nesting habits. 



The Nest and its Construction. 



The nest, as is well known, consists of a single layer of hexagonal 

 paper cells. It is modeled from a soft gray pulp which is a mixture 

 of fibers of weather-worn wood and a secretion from the wasp's 

 mouth. The little ball of semi-fluid pulp is applied roughly by means 

 of the fore legs, all along the edge of the cell to be extended, making 

 an irregular addition about four times as thick as the cell wall. The 

 wasp then walks back and forth for two or three minutes continually 

 touching the material with her antennae, and with her mandibles pats 

 and smooths it into shape. This operation extends the wall each time 

 from one eighth to one fourth of an inch, depending of course on the 

 size of the ball of material at the beginning. In addition to this, the 

 wasp applies a glutinous secretion which renders the paper tough and 

 waterproof, the nests built in the open being more thickly coated than 

 those sheltered from the rain and dew. 



The geometrical sense of the bees and wasps has long been a matter 

 of controversy. In Polistes, so far as I have observed, the first cells 

 always approach a circle in cross-section, and the six-sided form is the 

 result of the flexibility and the consequent compressing of the walls. 

 Once pressed into shape, the material added may take the same form, 

 and the artificer appears to possess a superior mathematical sense; 

 but that the cells are not intentionally fashioned thus may be seen by ex- 

 amining those first formed, or those comprising the margin of the nest 

 at any later stage of construction. These are always circular in out- 

 line. 



The Care of the Young. 



The larvae, which develop in a few days from the eggs, are fed from 

 this time until the beginning of the pupal stage both with nectar and 

 proteid matter. The nectar is obtained from flowers, is stored for a 



