6O2 



THE POPULAR SCIENCE MONTHLY. 



their nest with cotton or hair. (Fig. 5.) These labors of weaving 

 and sewing are preceded by the spinning of the thread. The bird 

 makes it itself by twisting in its beak spiders' webs, bits of cotton, 

 and little ends of wool. Sykes found that the threads used for 

 sewing were knotted at the ends. It is impossible not to admire 



FIG. 6. AN EDIBLE BIKDS' NEST AND THE SWALLOW THAT MAKES IT. 



animals who have skillfully triumphed over all the obstacles met 

 with in the course of these complicated operations. 



GELATIN NESTS. These are made by certain swallows who 

 nest in grottoes or cliffs on the edge of the sea. After having 

 collected from the water a gelatinous substance formed either of 

 the spawn of fish or the eggs of mollusca, they carry this sub- 

 stance 011 to a perpendicular wall, and apply it to form an arc of 

 a circle. This first deposit being dry, they increase it by sticking 

 on to its edge a new deposit. Gradually the dwelling takes on 

 the appearance of a cup, and receives the workers' eggs. (Fig. 6.) 

 These dwellings are the famous swallows' nests so appreciated by 

 the epicures of the extreme East, which are edible in the same 

 way as, for example, caviare. 



CONSTKUCTIONS BUILT OF EARTH SOLITARY MASONS. Cer- 



