HUNGERFORD: AQUATIC HEMIPTERA. 219 
were observed); the surface ornamented with a delicate tracery in the 
form of interlocking hexagons like a honeycomb or the facets of a com- 
pound eye. The egg is fastened in a sort of shallow cup which is of a 
leathery texture and dark brown in colour. The distal end, through 
which the nymph emerges, is provided with six to eight short lobes 
arranged ina circle. The appearance of the whole egg is mueh like that 
of a minute Grantia sponge. 
Dufour described the eggs of striata and hieroglyphica as acuminate 
at the free end and placed on a pad. White speaks of the eggs he 
describes as pyriform and attached at the broader end. He does not 
mention the pad or cup, nor does’ Heidemann, of Corixa mercenaria. 
It would be of interest to discover if there is a difference in this regard 
between different species of Corixids or whether in some cases the pad 
or cup has merely escaped observation.” 
It may be added that the ovum has a transparent button and tip, 
while the body of the egg is yellow. 
First Instar. 
“Length, about 1.15 mm. Width, about 0.55 mm. General appearance 
of adult, but wider in proportion to length. Head about three times 
as wide as long (dorsal aspect); distance from vertex to tip of beak 
about equal to the width between eyes (ventral aspect). Eyes promi- 
nent and conspicuous, deeply pigmented, facets relatively large. The 
beak is apparently 4-jointed, rather broad and conical. The black 
tips of the mandibles and maxille project slightly between the two 
halves. The former are somewhat shorter than the latter, curved, with 
minute serrations at the tips, and may be seen to extend into the head 
apparently up to the level of the eyes. 
“The antennz are 2-jointed, inserted far down toward the beak, the 
last joint about one-third the interorbital width in length. Tarsi all 1- 
jointed. Those of first leg, when at rest, curved over beak as in imago. 
First tarsi triangular in section, about one-third as long as those of 
third leg, 3% times as long as broad, oblong-triangular, broadly rounded 
above, the comb of bristles prominent. Tibia of second leg three-fifths 
the length of tarsus and squarish in section with the anterior angles 
armed each with a row of short bristles. Intermediate tarsus nearly 
eight times as long as broad, with a ventral row of long bristles and 
several rows of much shorter ones; tarsal claws weak, variable in length. 
Third leg sparsely bristled, tarsal joint slightly longer than the tibia or 
the femur, which are subequal. Body a little less than twice as long as 
broad, the posterior angles not so truncate as in later instars, provided 
and armed each with a half dozen rather long bristles. Lateral margin 
of body with bristles on posterior half only. 
“The tracheal system is comparatively simple, consisting of two longi- 
tudinal trunks sending off laterals in each abdominal segment, and one 
stout branch to each leg. Anterior branches supply the brain and the 
eyes.’ 
Second Instar. 
“A marked increase in size is noticeable, the length being now about 
1.9 mm., and the width about 0.9, roughly one-half as much. Head 
strongly convex, the frontal margin with a row of rather long bristles, 
longest in the middle, shorter toward the eyes. Posterior border deeply 
sinuate or arcuate. 
“Prothorax about as long as mesothorax, the two together a trifle 
longer than metathorax; the contour of the two together forming a 
narrow oval. Posterior margin of metathorax straight, anterior margin 
concave; its median length about equal to that of head. Abdomen trun- 
cate, 7-jointed, last joint about one-half as wide as first joint, termi- 
nated by two groups of rather long setz at the angles. 
“Tarsi all 1-jointed. First tarsus fringed with moderately long 
