BLACK REED WASP 397 



quarter as wide as long and closely resembles a sausage. The 

 spiders and the egg are now enclosed in a substantial cell 

 averaging twenty millimeters in length, by the insertion of 

 a double plug of mortar, six millimeters in thickness, half 

 of damp, dark-colored clay and half of the hard lighter ma- 

 terial. The nest is now abandoned by the parent wasps who 

 often start immediately to provision a second one. 



In two days the egg hatches, bringing to light a yellow- 

 white grub of thirteen segments. It commences feeding at 

 once upon the spiders, a process which may be observed un- 

 der the lens as a series of ripples or waves, commencing just 

 behind the head and continuing the entire length of the 

 body, one wave being completed or spent, before the fol- 

 lowing one sets in. It grows rapidly, but very steadily, in- 

 creasing each day in the same ratio until the last twenty-four 

 hours of feeding, when it gains somewhat less than during 

 the previous days. In all the larva or grub is full grown in 

 four days from the time it hatches. 



Upon finishing its meal, which lasts continuously for 

 four days, the larva spins a flimsy net work of silken threads 

 inside of which the cocoon proper is spun. This inner cocoon 

 resembles a tiny torpedo, rounded at both ends and ten milli- 

 meters in length. It is very neatly constructed of delicate 

 silk and coated all over the interior with a brown varnish that 

 hardens in contact with the air. 



Within this delicate cradle ten days later, the budding- 

 wasp undergoes pupation that wonderful process described 

 more fully in the previous chapter by which the footless 

 grub is transformed from a low and ancient form, to the 

 highest order of modern insects. The actual change from 

 gorged grub to a neatly folded, but colorless wasp is affected 

 in ten days, but it still has three hundred and twenty-eight 

 hours of confinement separating it from the light of day, 

 hours which must be passed quietly, lest injury result. 



As the hours go by, color at length flows through its 

 body and appendages, transforming opaque yellow to glis- 



