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 in a circle. The appearance of the whole egg is much 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 Ins tar. 



"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 maxillae 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 antennae 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 setae at the angles. 



"Tarsi all 1-jointed. First tarsus fringed with moderately long 



