WHITE-FOOTED WASP 405 



above the cocoon. The open top is now closed and reinforced 

 with silk, the strands crossing and recrossing in every imag- 

 inable direction so that the cocoon now appears in the shape 

 of a stubby cigar with an inverted parachute at one end. 

 The strings of the parachute extend above, where they are 

 fastened to the reed, thus suspending the entire cradle in the 

 center of the cell. 



The cocoon is now strongly supported from above. It 

 hangs perpendicularly in the hollow reed, head up, and no 

 matter how the larva thrashes about, there is no danger of 

 fallinff. Two or three hours after the last silken thread has 

 been spun, the grub continues its work, this time coating 

 the entire inner surface of its cradle with a transparent or 

 slightly yellowish fluid. A certain amount of this is brushed 

 directly upon the walls as it oozes from the creature's mouth, 

 but for the most part, the grub expectorates it upon its own 

 ventral surface. From here it is caused to flow over its en- 

 tire body by a strange series of muscular contractions. The 

 operation is repeated over and over until the writhing crea- 

 ture is thoroughly moistened by the secretion. As the grub 

 expands, contracts and turns its segments, the liquid becomes 

 incorporated with the silk of the cocoon, wetting it thorough- 

 ly on the outside. 



It is a varnish with strange properties that the larva 

 employs, — a sort of cement which will adhere only to certain 

 objects. When secreted it is transparent or nearly so. It 

 amalgamates at once with the silk and hardens in contact 

 with the air into a skin, purplish brown in color and brittle, 

 like the inner covering of a peanut. Strange to say it does 

 not adhere to the larva, nor turn color until compounded 

 with the other material of which the cocoon is made. 



The entire process, of spinning and varnishing, requires 

 two full days. The grub then expels a large pellet of waste, 

 the accumidation of six days of feeding, in the bottom of the 

 cocoon. This hardens rapidly into a solid cake in a few hours. 

 Sixteen days later pupation takes place. 



