HUNGERFORD: AQUATIC HEMIPTERA. 183 
tive creature. The other nymphs were still slow and inactive. On May 
24, at five p.m., two were still alive, though their guard hairs were non- 
functional. This tardy coming to the surface seems to be a feature in 
the behavior of the newly hatched of this bug. The habits of the adult 
and the needs of the larve appear to be different from the others studied. 
The last adult of the overwintering generation was taken early in 
July. The species was too rare to accord satisfactory study in nature. 
Here follows a description of the egg and young nymph: 
The Egg. 
Size. Length, 2.21 mm.; height, viewed laterally, .78 mm.; width 
- viewed from above, .754 mm. 
Color White, with surface quite strongly reticulate so that surface 
is rough. The chorion is quite tough. 
Shape. Elongate oval, micropylar end somewhat truncate; caudal end 
more pointed. 
As with other Notonectid eggs the micropyle is a curved truncate 
cylindrical peg. 
The egg is attached to the plant stem or other support by a trans- 
parent pad of mucilaginous material. This egg is proportionately quite 
large. See the drawings on plate XIX. They are drawn to the same 
seale and show how much larger this egg is than that of Notonecta ir- 
rorata, a bug of nearly the same size. 
First Instar. 
Size. Length, 2.73 mm.; width of both, 1.248 mm.; width of head, 
1.092 mm.; width of front of head between the eyes, .546 mm.; distance 
between the eyes, .442 mm. 
Color. Body white and abdomen and limbs of newly hatched trans- 
parent, the hairs smoky, eyes red and prominent, antenne and beak dark. 
a 
§ 
The limbs are also sometimes dark in the older nymphs. 
Structural Characters. The antenne are directed downward, 3-seg- 
mented, basal segment very short. The tarsi are 1-segmented and end in 
two claws each. The claws of the hind tarsi are not conspicuous. The 
middle femora have, on their posterior margin, at least 2 spine-bearing 
tubercles. The posterior femora have 10 or 11 stout spines (on posterior 
margin) plus 2 longer ones at distal end. 
Notonecta irrorata. 
Habitat. This is a handsome bug of velvety brick red and black, and 
one of the largest species of back-swimmers. Bueno tells us that it likes 
the shadows of the bank, of overhanging limb, or of aquatic vegetation. 
Surely its mottled pattern of dark colors would serve it well in such 
haunts. We have found it very abundant at the field station and in the 
Meadow pool at Ringwood Hollow, Ithaca, N. Y. 
Hibernation. It spends the winter months in the deeper ponds and 
spring-fed open pools, flying from these quarters to shallower waters for 
breeding. At Ringwood Hollow this bug was present in considerable 
numbers in the rather deep leaf-strewn pool just west of Winterberry 
4 
