84 
Some Solitary Wasps of Texas. 
the instinct to store the nest quickly and close it up over the un- 
hatched egg, runs the development of the stinging instinct, which 
aims to paralyze the prey to preserve it for the future offspring. 
Thus Microbembex , which is the most generalized in the mode of 
procuring food, seldom needs to sting her prey, for she nearly al- 
ways finds it dead. When she stings, it is to kill and from a single 
observation I judge her to be very awkward in the application of 
her sting. The five caterpillars I saw her carry into her nest were 
all dead. The greater part of the caterpillars captured by Ammo- 
phila or Odynerus, wasps that specialize in that kind of prey, are 
brought into the nest merely paralyzed instead of killed outright. 
B ember tex and other fly-catchers sting their flies to death with 
a single prolonged sting as I observed in Chap. IV. This suggests 
the idea that the primary purpose of the sting is to overcome the 
victim. 
Among most of the other solitary wasps the tendency to merely 
paralyze the victim is more or less perfectly developed. Bugs, 
grass-hoppers, bees, spiders or caterpillars are sometimes brought in 
stung to death, but often they live from a few days to many. The 
nearest approach to perfection is reached in the Ammophilae. So 
nearly perfect is the habit here that Fabre was led to assert that 
two conditions always obtain with Ammophila’s caterpillars and are 
absolutely essential to the perpetuity of the species : first, that the 
caterpillar must be sufficiently paralyzed to insure the safety of the 
egg, yet secondly, it must remain alive sufficiently long to furnish 
fresh food for the growing larva. Though Fabre has noted a 
slight variation in the number and order of the stings administered 
he insists of the necessity of stinging the caterpillar in the middle 
segments, one of which is to receive the egg, and his observation^ 
seem to bear him out. In Chap. II, I have given my own observa- 
tions on five caterpillars of - Ammo phila procera which fulfilled to a 
nicety the condition thus laid down by Fabre. In each case the 
caterpillar lived long after the egg should have hatched, yet in each 
case the caterpillar was sufficiently stung in the middle segments to 
insure the proper quiescence. It must be said, however, that the 
five caterpillars thus observed are not sufficient to yield conclusive 
results. In this connection we should listen to the Peckhams, whose 
opinions, diametrically opposed to those of Fabre on the question of 
the stinging and other instincts of wasps, yet seem to me to be well 
established. Fabre argues that the wasp’s actions are the result of 
an automatically perfect instinct which allows no variations. The 
Peckhams combat this view, holding that, in their study of wasps. 
