254 Trans. Acad. Sci. of St. Louts 
carpenter-bees nesting in the same place did not come 
home during the storm. They saved themselves a drench- 
ing, and after an hour or so, when the storm had ceased, 
they came flying blithely in. We have recorded else- 
where in these pages that the rain drops on the leaves 
near by were eagerly lapped up by 4. abrupta and used 
in their work of excavating, and I should not be sur- 
prised if drops of dew in the early morning were gath- 
ered for the same purpose. 
While we find evidence of a certain amount of de- 
struction of life by rainstorms, insects of a great variety 
beaten down by the rain, and their nests in the earth 
cut open or buried deeply by the erosion of the soil, yet 
the rain is not without its benefits also. It has been 
noticed that immediately after a rain following a long 
dry period, there was a surprising increase in the pop- 
ulation of burrowing Hymenoptera. For a time I east 
this aside as mere coincidence, until the evidence seemed 
too strong to be thus discarded. Why this sudden ap- 
pearance after the rain, and what is the direct action of 
the rain upon their emergence? There is no physiolog- 
ical connection, I am sure, but merely a physical relation. 
During a period of drought the earth had become ex- 
tremely hard; hence the emergence of these young 
ground-dwellers was rendered impossible. Perhaps they 
could wait for a time, but surely not for long. We have 
no way of knowing how many or what proportion of 
them perished in their futile attempts to break through 
the brick-like earth. The rain came and softened the 
earth, and lo! they appeared as if by magic. No doubt 
there was heavy elimination here, but in this case one 
cannot call it the survival of the fittest; it was only the 
survival of the lucky, and how do we know but the 
