224 THE UNIVERSITY SCIENCE BULLETIN. 



In one large aquarium jar was placed ground cattail stems to the 

 depth of one-half inch. The cattail had been soaking all winter in the 

 pool and was readily reduced to a flocculent mass by passing it through a 

 grinder. After drawing off the water two or three times, and replacing 

 with fresh water, the jar was ready for use. 



Bugs of this species were placed herein and maintained themselves 

 throughout the season without further attention. The overwintering 

 nymphs became adult, mated, and laid their eggs, which hatched in due 

 time. On July 6 all of the adults were dead and nymphs up to the sec- 

 ond instar were noted feeding. The hot rays of the sun shining through 

 the glass wall of the jar were not favorable to the bugs, though some 

 survived, for by August 7 there were several nymphs in the fourth or fifth 

 instars. August 21 three adults had arrived and the remaining nymphs 

 were in fifth instar. These became adult sometime during the first week 

 in September. The rearings were not followed closely from this time 

 on, but the evidence on hand seems to show that these adults that emerge 

 the last of August give rise to the nymphs that overwinter. Thus there 

 are two generations a year, one overwintering as a nymph and becoming 

 adult in June, the other coming on in July and emerging in late August. 

 Some fifty pairs of new fledged adults of the first generation were placed 

 in petrie dishes in an attempt to ascertain the number of eggs each 

 female would lay. In every case the bugs died without laying a com- 

 plete egg complement. Floating cages were placed in Beebe Lake in a 

 like effort, but were disturbed, and after two or three attempts the 

 project was abandoned. From the immense numbers of these bugs 

 present in suitable waters, there is every indication that they are prolific 

 and capable of foraging in close quaters. Since both nymphs and adults 

 have been recovered from fish stomachs, they afford a possible source for 

 the increase of a food supply by their artificial propagation. Of all the 

 Corixids with which the writer is familiar this species presents some of 

 the most likely possibilities in the regions where they may be found. 



The absence of functional wings in the majority of them and ability 

 to forage in close quarters are factors quite in favor of their use in pools 

 set apart for their artificial propagation. 



DESCRIPTION OF STAGES. 



The Egg. 



Size. Height, 0.546 to 0.572 mm.; diameter, 0.325 to 0.39 mm. The 

 egg when first laid inclines to the minimum measurement, and when con- 

 taining well-developed embryo attains the greater dimensions. 



Shape. Varies with development within, asymmetrically ovoid. An- 

 terior end more slender and terminating in the usual micropylar tip. 

 Greatest diameter about the middle of the egg. The shape of the freshly 

 laid egg is more slender than that of the one ready to hatch. 



Color. Pearly white when first laid, darkening to yellow as embryo 

 develops within. When ready to hatch the color is yellow, the base of 

 the micropylar peg is black, and the claws of middle legs of the nymph 

 within are visible as dark lines. The eyes are red, and the dorsal ab- 

 dominal glands show through as faint pink blotches. 



