The solitary wasps have stings whose venom is much less powerful than that of the bees. Fabre declares that his experiments convince him that the reason may lie in the fact that for paralyzing its prey the wasp needs only a weak poison whereas when the bee stings it does so in self-defense and it stings to kill. The busy mud dauber females build their nests of mud brought from the nearest puddle and in each carefully made cell lay an egg and around it pack the paralyzed insects on which the voracious little grubs begin to feed as soon as they hatch out. By the time the young grubs have eaten up the food that has been so thoughtfully supplied by their parents and have changed from grub to pupa and emerged as flying, stinging wasps, their parents are dead and gone. Imagine, if you can, a civilization in which the mothers slave for offspring which they never see, and the children grow up with no education, yet possessed of all the knowledge that their parents had. As Sharpe remarks, the solitary wasps are among the most instinctive creatures of the animal kingdom. [Illustration] THE FOOD OF A MUD DAUBER'S BABY This little white spider I found in the nest of a mud dauber wasp. How long this white spider would have lived its paralyzed existence I do not know. Fabre has watched insects so paralyzed for six weeks, and this one was on my table for several weeks in June without moving and without showing any sign of decay. We are accustomed to think of the wonders of cold storage as a result of this age of invention, and to look upon its achievement as the accomplishment of the human brain. The mud dauber, in common with most of the so-called solitary wasps, possesses the means of paralyzing the nerve centers of its prey and thus preserving it alive for weeks in the nests of the baby wasps. With the most amazing aim it darts its poison sting between the joints in the armor plate of its victim and touches with a drop of poison one of the nerve ganglia which lies on the abdominal side of most insects. Fabre has shown that the same result can be produced by a needle and a drop of ammonia, and insects paralyzed in this way hang, as it were, between life and death for weeks or months. If too heavy a dose is given the insect dies in a few hours and putrifies in a few days, and if given too light an application it soon recovers. Different insects require different amounts of the poison to paralyze them and the solitary wasps make mistakes just as man would do. According to Fabre these insects have also discovered that in certain species of their prey the nerve ganglia are grouped close together and can be easily reached with the poison while in others the ganglia are separated, and each ganglion must be touched.