94 THE UNIVERSITY SCIENCE BULLETIN. 



Seven days represented the average for 53 eggs in July. The red eye 

 spots appear in such a period about the third or fourth day. A few 

 eggs required 23 days to hatch in May. 



Hatching. The hatching process had not been recorded for our Ameri- 

 can forms, and the w^riter was delighted for the opportunity to study the 

 process in detail. Notes and drawings were made at the time, and are 

 given herewith. While at Ithaca, N. Y., there was available in the private 

 library of Mr. J. T. Lloyd, a set of the "Annals de Biologie Lacustre." 

 In volume IV, page 327 (1911), Brocher, under the title "Observations 

 biologiques sur quelques insectes aquatiques," gives an account of the 

 oviposition, the egg and the larva of "Lemnabates." He figures the egg 

 and the postnatal molt of an escaped njrmph. In hatching, the body of 

 the egg swells in one spot and gradually the shell begins to split longi- 

 tudinally down one side. The embryo bulges through and in a few 

 moments the red eye spots come to view and the shiny, black "eggburster" 

 of the embi-yonic envelop (postnatal molt) shows between the eyes. (See 

 pi. XIII, fig. 7.) Gradually with slight bulging movements the embryo 

 works its way out until it occupies a position almost at right angles to the 

 egg shell. It is still inclosed in the thin membranous envelop. The envelop 

 now splits at the cephalic end (pi. XIII, fig. 10), and as it is cast the 

 antennas and legs gradually appear uncovered though still folded against 

 the ventral side. The head (so long and slender in the hatched bug) is 

 bent at a position caudad of the eyes so that in the embryonic envelop the 

 most of the head is folded on the ventral side of the embryo, the beak 

 reaching nearly to the caudal end. One of the eggs observed during 

 the hatching was just beneath the surface of the water and the embryo 

 coming forth was partly below and partly above. Yet when the antennae 

 were liberated and the head allowed to straighten and the limbs freed, 

 the tiny almost transparent pale green nymph had little trouble in arriv- 

 ing at an upright position on the surface film. 



Behavior of Newly Hatched. The newly hatched bug can walk upon 

 the surface of the water and is soon ready to look for something to eat. 

 It begins the precarious existence of the surface dwellers. A close study 

 of these creatures as they go about their daily activities in field and 

 laboratory, brings home to one the tragedy of life with its grim "survival 

 of the fittest." We were watching one nymph disengage itself from its 

 shell. It was a slow laborious process, this particular coming into the 

 world. We were relieved in a way when its postnatal molt was completed. 

 Yet this feeling was short lived, for hardly had this new life righted itself 

 upon the surface film and taken an inventory of its surroundings before 

 there stalked up behind it, as we watched, another tiny nymph. This 

 second fellow was a little darker (he had hatched a few hours before). 

 Slowly but with definite purpose this murderous nymph slipped up behind 

 the unsuspecting newly born, with beak outstretched before it. A sudden 

 movement, and with a squirm of distress the little bug we had watched 

 come into the world was caught upon the stylets of his brother, and its 

 brief life of a few moments was over. Such is the life of the pool ! Then, 

 as we watched, its poor body became the banquet table of two of its 

 brothers. One with its beak inserted in the joint between the femur and 



