THE CANADIAN ENTOMOLOGIST. 10 



o 



force it out. It is certain, however, that they have some connection with 

 the respiratory system. The functions of the pile were long since recog- 

 nized by Burmeister." 



Hereafter follow the notes made from the various instars bred : 

 Ovum. — Shape : Imperfectly oval, the upper end being the more 

 pointed, the lower rounder. Size : Long., 2 mm.; lat. i mm. at widest 

 part. Colour : Light yellowish-brown, shading into dark brown, nearly 



black at the upper end. When freshly occluded, the ova are of a light 

 yellowish hue. Markings: Under a high power (150 diameters) the 

 corium is seen to be shagreened with very small graining, otherwise 

 entirely free from the more usual condition of ornamentation in the 

 Hemiptera. During incubation the ovum increases in size and changes 

 in form. Just before emergence it is as follows : — .Shape : Elongate oval, 

 noticeably tapering from the apex to the base. Size : Long., 3 mm.; 

 lat., I.I at greatest breadth. 



The ova, as already noted, are deposited by the female on the back 

 of the unwilling male. They are embedded about half their length in the 

 waterproof glue mentioned previously. The preceding descriptions of 

 the ovum are not perhaps as accurate as th.ey should be, since they have 

 been drawn up from alcoholic material. The peculiarity of growth during 

 embryonal development is not unusual, the ova of the various water-bugs 

 I have bred showing it more or less, but none so markedly. ^^ 



The 200 or more ova occluded in my aquaria had a period of incuba- 

 tion of between six and twelve days. The ova from which were raised 

 the three individuals carried through to maturity, took respectively seven 

 and tvv'o eleven days. As a general rule, the greater part of the eggs hatch 

 simultaneously, and the male then sheds its unwelcome burden, the 

 unhatched remainder, if fortunate, emerging a day or two later. The 

 nymph comes out through a round lid that splits off the top of the egg and 

 is attached thereto by a hinge extending about one-quarter the circumfer- 

 ence. The process of emergence I very fortunately saw, and the following 

 account is a transcript of my notes made as the little bug came out of its 

 shell. After the round lid is split off, the head is gradually pushed out. By 

 slow successive heaves, the remainder of the body is drawn out until 

 it stands erect, with the chorion as a base, holding the posterior 



9. Handbuch, \'ol. II, p. 195. 



10. Cf. Bueiio, Journal Xew York Entomological Society, \'ol. XI, p. 168. 



