AQUATIC IXSECTS IX NEW YORK STATE 473 



"uiiicb is 1.3mni long', and about one third as wide, ellipsoidal, 

 translucent, sordid white, with a delicate shell, and surrounded 

 and separated from the adjoining eggs by a thin layer of the 

 same white albuminous material which covers the whole. The 

 outer layer forms a compact arch, with the anterior ends point- 

 ing inward, and the posterior ends showing like faint dots 

 through the white covering. Those of the marginal row lie flat 

 on the attached surface; the others gradually diverge outwardly 

 so that the central ones are at right angles with said object. 

 Beneath this mantled layer the rest lie on a plane with the leaf, 

 those touching it in concentric rows; the rest packed in irreg- 

 ularly. Before hatching, the dark eyes of the embryon show 

 distinctly through the delicate shell, and the eggs assume a 

 darker color, which contrasts more strongly with the white 

 intervening matter. 



The egg-burster [ruptor ori) has the form of the common im- 

 nmture mushroom, and is easily perceived on the end of the 

 vacated shell." 



Prof. Riley's description of the ''egg-burster" agrees exactly 

 with the appearance of the micropylar projection, and this is 

 the only appendage I have found on the eggs either before or 

 after the larvae have hatched [flg.20]. 



The eggs are found on trees, vines, leaves, stones, bridges, etc, 

 usually over running water, but sometimes at a very short dis- 

 tance to one side of the stream. 



Life history of Corydalis cornuta 



Riley and others have given accounts of the life history of 

 this species, but by careful tracing I have been able to add a 

 few points. 



The young larvae of an egg mass all hatch in a single night, 

 crawl from under the mass and soon drop or crawl to water. 

 The young differ from the older larvae in having relatively larger 

 heads and mouth parts, only three jointed antennae, and rela- 

 tively longer filaments and legs. Riley observed that they lack 

 the ventral spongy tracheal tufts. These tufts do not appear 

 till a later molt. Riley therefore concluded that these tufts 

 are for the purpose of adhering to stones, and not for breathing. 

 The structure of these (showing tracheae), the absence of other 

 suitable gills, the regular movements of the tufts w^hen a larva 

 is actively respiring, as when placed in water from which the 

 -air has escaped — all these indicate the true purpose of the tufts. 



