The Microscope. 329 



cells once for all. Noticeable among these is the mud-dauber, 

 Pelopasus. The food varies according to the taste of the spe- 

 cies — spiders, caterpillars, flies, worms, beetles, etc. Some 

 species select caterpillars for the food of their progeny. But 

 how is the little grub of the wasp to feed upon such prey ? If 

 the caterpillar were dead, it would decay like other animal 

 matter and be unfit for food ; if unharmed, it would assuredly 

 injure the egg or larva ; nor would it sul)mit to be eaten. So, 

 a fortiori, as regards those species which store their cells with 

 spiders. The living spider is carnivoi'ous and would consume 

 the larval wasp rather than vice versa. What does the wasp in 

 this dilemma? It stings its prey, thereby deprives it of motion, 

 and a store of fresh food is thus at the service of the young 

 was}). Packard sa3'S : " The sting of those wasps which store 

 up insects for their young, penetrates the nervous centres and 

 paralyzes the victim without depriving it of life, so that it lives 

 many days, A store of living food is thus laid up for the 

 young wasp. After being stung, the caterpillars will transform 

 into chrysalids, though too weak to change into moths." 



Here is truly a remarkable thing that a wasp should be so 

 unerring with its sting as to hit the nervous centres in defiance 

 of the struggles of its prey. The victim is rendered powerless 

 by the sting and a state of ' motionless lethargy ' ensues. Is it 

 due to paralysis, or is it something else? It must be admitted 

 to be paralysis when a caterpillar goes on to develop into a 

 chr^'salis, but never attains the adult state. How is it, however, 

 with the spiders. They do not lose their plumpness nor their 

 color ; but do they go on to moult ? This never happens to the 

 best of my knowledge. The duration of this lethargic state is 

 sometimes remarkable. Thus Mr. F. Dienelt records an instance 

 where such spiders had been kept eight months and over, and 

 through a hard winter. This fact challenges attention and leads 

 to unlooked-for influences. Can spiders exist eight months in a 

 paralyzed state ? During all this time they have been deprived 

 of food and water, and yet the abdomen is plump and they look 

 as if only fresh-gathered. A paralyzed vertebrate must die as 

 soon as the reserve-supply stored in the system is exhausted. 

 Why does not the invertebrate also ? The laws of the nervous 

 system cannot change among the classes of animals. After 

 an undefined time with most of the captures, and probably 



