﻿OF THE STATE ENTOMOLOGIST. 127 



ever, they were seen to consist of sub-oval or circular swellings, with more or less 

 white splashed around them ; and upon still closer examination, they proved to be 

 egg-masses. They were generally attached one to the upper surface of a leaf either of 

 Sycamore, Elm, Cottonwood or Grapevine; but sometimes there were several on the 

 same leaf, and at others they occurred on both sides of the leaf It was evident that 

 the leaves were objects of attachment only, * and from the fact that only those which 

 overhung the water were selected by the parent, it was natural to infer that the spe- 

 cies was aquatic in its larva state. Yet the egg-masses greatly puzzled me, as indeeed 

 they did all naturalists to whom I referred them ; for the eggs of the larger water- 

 beetles were known, those of Corydalus were supposed to be known, and there was 

 only one other water insect in North America, viz : Belostoma grandis, large enough 

 to be capable of laying such a mass. But these eggs were evidently not Heteropter- 

 ous. 



Patiently waiting till the eggs hatched, I recognised at once, in the young larva, 

 the characters of Corydalus cornutus, with the full grown larva of which I was familiar ; 

 and upon dissecting the abdomen of a female Hellgrammite, the nature of the 

 curious egg-masses was fully confirmed in the perfect identity in shape and arrange- 

 ment of the eggs composing them, and of those in said abdomen. 



The egg-mass of Corydalus eornutus is either broadly oval, circular, or (more excep- 

 tionally) even pyriform in circumference, flat on the attached side, and plano-convex on 

 the exposed side. It averages 21 mm. in length, and is covered with a white or cream- 

 colored albuminous secretion, which is generally splashed around the mass on the leaf 

 or other object of attachment. It contains from two to three thousand eggs, each of 

 which is 1.3 mm. 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 pointing inwards, 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 vaulted layer the rest lie on a 

 plane with the leaf, those touching it in concentric rows ; the rest packed in irregularly. 

 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 young crawl from under the mass, and leave the vaulted covering intact. 

 They all hatch simultaneously, and in the night. 



The egg-bursterf has the form of the common immature mushroom, and is easily 

 perceived on the end of the vacated shell. The young larvaa crawl readily upon dry~ 

 surfaces, with their tails hoisted in the air, and live for a day or more out of water ; 

 but when hatching out over an aquarium, they instinctively drop to the water, where,, 

 after resting for a while, with their bodies hanging down and their heads bent forward 

 at the surface, they swim to the bottom by whipping the body from side to side very 

 much as a mosquito wriggler does. Here they secrete themselves and remain until, in 

 the course of a few days they perish. They cannot be reared in confinement, and 

 running water is doubtless as essential to them as to the full grown larva. 



The newly hatched larva is almost colorless and differs from the full-grown larva, 

 in the relatively longer legs and lateral filaments ; in these last being smooth and not 



* Since this was written, I learn from Mr. Liiitiier, of Albany, N. Y., tliat he has found these egg- 

 masses attached to roclis in the Mohawk river, thougli he liad no linowledge of their parentage. 



1 1 am not aware that this special structure has been named. It is gener.illy, if not always, a part 

 of the ambion, and is common to many insects, though varying much in form. It may be known as the- 

 ruptoT ovi. Dr. Hagen has called it the "egg-burster," while erpetologists designate as the" egg- 

 tooth, " a structure having the same purpose. 



