PI, XVII. — Eggs of water insects: i, mayfly, Siphlnriic^ 

 eggs containing embryos, shells with slit through which 

 insects have hatched; at the center note the head projecting 

 from a shell; 2, mayfly, Siphhirus, with shell from which it has 

 hatched; 3, eggs of horse-fly, Chrysops, on an iris leaf; 4, eggs 

 of caddis fly, TricBnodes, on underside of lily pad ; 5, egg cocoon 

 of hydrophilid beetle, on underside of lily pad. 



Photo, by A. H. Morgan 



