404 AISTNUAL EEPOET SMITHSONIAN INSTITUTION, 1919. 
on, but no evidence of hatching was found until the 24th. Egg 
laying had been at its height about the 10th of June, so fully seven 
weeks had elapsed already and no nymph had yet been seen. Pos- 
sibly the normal hatching was retarded b}^ the heavy rains that fell 
almost continuously during the 10 days previous. Many eggs ex- 
amined v/ere found dead and turning brown, but the percentage of 
such was small. On the 24th there was no rain and the sky was 
only partly cloudy. The usual search revealed two nymphs on a 
punctured twig of a small chinquapin, but that was all. Some of 
the nests examined showed a few empty shells, but, judging by their 
proportion, the great majority were still unhatched. 
The next day, the 25th, was hot and bright all day. The trees were 
inspected in the afternoon. Their twigs had been bare the day 
before. Now, at the entrance holes of the egg nests were little heaps 
of shriveled skins, thousands in all, and each so light that the merest 
breath of air sufficed to blow it off ; so, if according to this evidence 
thousands of nymphs had hatched and gone, the evidence of as many 
more must have been carried away by the winds. An examination 
of many eg^g nests themselves showed that over half contained 
nothing but empty shells. Whole series were thus deserted, and 
usually all or nearlj^ all of the eggs in any one series of nests would 
be either hatched or unhatched. But often the eggs of one or more 
nests would be unhatched or mostly so in a series containing other- 
wise onl}^ empty shells. Delay appeared to go by nests rather than by 
individual eggs. 
As a very general rule the eggs nearest the door of an egg chamber 
are the ones that hatch first, the others following in succession, though 
not in absolute order. But unhatched eggs, if present, were always 
found at the bottom of the nest, with the usual exception of one or 
two farther forAvard. Only occasionally an empty shell v>^ould be 
found in the middle of an unhatched row. If the actual hatching of 
the eggs was observed in an opened nest several nymphs would 
usually be seen coming out at the same time, and in nearly all cases 
they were in neighboring eggs, though not always contiguous ones. 
So this rule of hatching, like most rules, is general but not bindmg. 
The procedure of the female in placing the eggs leaves no doubt 
that the first laid ones are those at the bottom of the cell, showing 
that the order of laying has no relation to the order of hatching, 
except that it is mostly the reverse. It seems hardly reasonable to 
suppose that the eggs nearest the door are affected by greater heat 
or by a fresher supply of air, so I would suggest that the order of 
hatching may be due simply to the successive release of pressure along 
the tightly packed rows, giving the compressed embryos a chance to 
squirm and kick enough to split the inclosing shells. YVhen hatching 
