1881.] Entomology. 815 
itself is composed of two parts, viz: (1) a hard spatulate piece of 
compact brown silk, smooth externally and with the two edges of 
the tapering end curled inside and welded at tip so as to form a 
we 
Fic, 1.—Hydrophilus: a, larva of H. piceus; c, pupa of same; d, opened ege- 
case showing arrangement of eggs; ¢, closed do; after Blanchard ; b, S of &. tri- 
angularis * f, antenna of same; g, front tarsus 2; 4, do of '; z, stout sternal 
Spine, side view; after Riley. 
Stout point (Fig. 2, ¢), and (2) a somewhat cuneiform air-chamber 
1g. 2, d, h). ere is, second, the egg-case proper (Fig. 2, 2), 
and, ¢hird, the outer bag or covering (Fig. 2, . The air- 
chamber has an external, slightly bulging covering (@) of the same 
character as the outer bag of which it forms a part, but of some- 
what darker silk, while the inside (4) consists of loose brown 
silk forming large cells and connecting with the spine, the hollow 
Parts of which are in fact filled more or less compactly with these 
Ah Fic. 2.—Egg-case of Hydrophilus triangularis : a, fall side view ; c floater ; d, 
ar-chamber ; Jf, outer bag; e, opening; g, floater detached, showing inner side; 4, 
silken fibers. The egg-case proper, which is of a white, rather 
flimsy or paper-like silk is partially suspended posteriorly from 
the roof of the outer bag by white loose silk, but is principally 
attached to the inferior side of the air-chamber, which so narrows 
toward the broad end of the spatulate piece that this last is vir- 
