44 INSECT BEHAVIOR 



and open at the upper end. Through this opening a ring of silk is 

 spun, two millimeters in height, with a scalloped edge, the point of 

 each scallop forming one of the thirty or more strands extending 

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

 silk, the strands crossing and recrossing in every imaginable 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 ex- 

 tend 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 per- 

 pendicularly in the hollow reed, head up, and no matter how the 

 larva thrashes about, there is no danger of falling. 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 entire body 

 by a strange series of muscular contractions. The operation is re- 

 peated over and over until the writhing creature is thoroughly moist- 

 ened by the secretion. As the grub expands, contracts and turns its 

 segments, the liquid becomes incorporated with the silk of the cocoon, 

 wetting it thoroughly 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 



