138 THE UNIVERSITY SCIENCE BULLETIN. 
Mating. As in M. americana, described by Bueno. 
Oviposition. The writer finds the eggs placed much as in M. ameri- 
cana, in a mass of jelly-like material just above the surface of the water 
and attached to pebbles, stones, ete. Bueno noted them “on the under 
side of duck weed. The head end pointed to the edge of the leaf.” Each 
egg is upon a stained pad of gelatinous matter as if it had used too 
much adhesive. When first laid the egg is very white. 
Incubation. Bueno gives from 7 to 23 days. The writer has kept 
many batches under observation in July, and finds the time to be around 
six days. One lot contained 145 eggs. The darker color and the red 
eye spots mark the older eggs. Thirty-two eggs laid July 25 showed 
on the 27th faint yellowish circular spots, which later are the red eye 
spots. On the 29th they hatched. 
Hatching. Bueno says the eggs split longitudinally for 4% of their 
length, and through this the nymph escapes. He looked for, but failed 
to find, the “amnion or molt.’ The writer finds that the postnatal 
molt does occur and that it bears an “egg burster” like the Gerris. 
One was observed under the binocular to be just coming out. Swathed 
in the thin membrane it struggles out. The black, shiny knife between 
the eyes is attached to, and shed with the postnatal molt. Before this 
membrane breaks, the legs are seen to curl around the tip of the abdo- 
men. The antenne, beak and legs are outstretched upon the ventrum. 
See plate XII for figure of the nymph within the egg. 
Fecundity. Bueno says a female holds two eggs at a time. The 
writer noted 6 females that laid 145 eggs in five days. This means 
nearly 5 eggs per female per day. It takes from 10 to 20 days to reach 
the adult stage. 
Molting. In molting from one instar to the next the process is about 
as follows: The old integument becomes quite rigid and sets upon the 
water in a substantial manner. It splits longitudinally for some distance | 
down the dorsum, and the triangular piece between the eyes splits out 
forward as in the large Gerrids. The antenne are directed laterally and 
downward. The newly emerged nymph is white with red eyes. It rests 
for a time perched upon the old nymphal skin. 
Feeding Habits. In the rearings these little bugs were given plant 
lice and house flies. In shallow petries they make out very well if only 
there are Ostracods and Daphnians present in the water. The writer 
has seen little first instar bugs eat Ostracods larger than themselves. It 
is interesting to watch them maneuvering to pick out an Ostracod that is 
floating with one surface at the film. The bugs feel around with their 
little beaks, the terminal segment twisting here and there, playing over 
the smooth impervious surface for a vulnerable point. If this is not 
successful they will employ their fore legs in an attempt to roll over the 
little Crustacean. The Ostracod that moves is the one that attracts their 
attention and it is sought out and molested by these ever alert and 
watchful pygmies of the surface. Here one succeeds in driving home 
his barged stylets and with a backward jerk does an astonishing thing, 
