308 B. GRASSI AND A. SANDIAS. 
Winged imagos occur from the beginning of April to the 
middle of June (a few stragglers being exceptionally found as 
late as September). 
The remaining forms are present, as a rule, all the year 
round, except the kings, or incipient royal forms of either sex. 
The latter have already been repeatedly referred to, and 
must receive further notice in the following chapter. 
Lastly, I must not omit to mention that nymphs of the first 
form are absent in some years from certain nests, which have 
probably been orphaned at a previous period. 
6. Duration of Development, Life, &c. 
The eggs hatch fifteen or twenty days after they are laid. 
Many observations lead me to conclude that the very young 
larvee found in the winter do not develop farther than the 
nymph of the first form in the following summer, and there- 
fore must certainly live through a second winter before acquir- 
ing wings; e.g. larvee born in October, 1889, will not have the 
wings fully developed until April, 1891. 
Thus, too, the complete or almost complete absence in 
October and November of examples with 14—16-jointed an- 
tennz and distinct wing-buds compels me to believe that those 
hatched in May have become nymphs already, or else that 
they do not yet possess fourteen antennal joints. The latter 
hypothesis is correct; for if the former were, a much larger 
number of nymphs ought to be found in particular nests than 
is actually the case. 
A small colony obtained in a glass jar was furnished with 
a number of fully winged individuals in the early part of May ; 
on the 20th of December it contained, beside the other in- 
habitants, five workers with 12—14-jointed antenne. 
Several orphaned nests were placed in large glass jars in 
January ; next October they still contained small specimens 
with 13—14-jointed antennz, while no substitute forms had 
developed. 
These further facts agree sufficiently with the hypothesis 
which I regard as correct. 
