406 AMERICAN SPIDEKS AND THEIR SPINNINGWORK. 



of special weakness and inability for defense. The closure of the domicile 

 just before cocooning is explained by the maternal instinct which drives 

 mothers into hiding at that crisis period of life. But August is the time 

 when insects are most plentiful in our climate, and one would think that then 

 Tigrina would keep her burrow, open in order more freely to prey upon 

 insects. 



The explanation is certainly found in the presence of a species of Digger 

 wasp, Elis 4-notata Fabr. (Scolia). (Plate V., Fig. 3.) She belongs to the 

 arachnophagous species, and, although the mother appears to feed 

 ^^ ® upon nectar and honey, the grub feeds upon the juices of spi- 

 ders, and the particular species affected by the wasp larva is 

 Lycosa tigrina. The wasp is large and strong, has smoky brown wings 

 with a strong purplish blue iridescence, and two bright orange spots on 

 either side of the abdomen. She runs over the ground swiftly, peering 

 here and there into various recesses, until she alights upon an open bur- 

 row of Tigrina. Down into this she plunges, and soon returns dragging 

 up the inhabitant, which she has already paralyzed with her powerful 

 sting. Woe now to all spiders with unclosed doors, for Elis is sure to 

 find them ! 



Sometimes two wasps are hunting in the same vicinity, and when one 

 finds a spider the otlier tries to wrest it from her. A furious battle en- 

 sues. The combatants drop the prey and clinch in conflict, seemingly try- 

 ing to stab each other with their stings. The victorious party returns to 

 the spider, which is often heavier than herself, and proceeds to drag it to 

 her nest. She moves backward for a time, drawing it over the ground, 

 then tries flying a short distance, but the burden is so heavy that she soon 

 comes to the ground again. Slie is so active and quick in her movements 

 that one has to walk quite fast to keep abreast witli her. She carries the 

 spider several rods from where slie obtained it, lays it down on the gravel 

 walk, and liunts over the ground. Presently she finds a burrow which she 

 liad previously dug, takes up her spider, and disappears within. 

 _ . J She comes out empty handed and proceeds to fill up the hole 

 with the earth she had thrown up. She works so rapidly that 

 one can scarcely tell which feet she uses most. She seems to dig with 

 her fore feet and rake the earth in backward with her hind feet. Soon 

 the hole is full. And now she makes a battering ram of herself by rapidly 

 striking her body on the ground, as if to pound the earth down. This 

 done, she rakes the ground all over and around the place to make it level, 

 then collects small pebbles in her mandibles and lays them over the spot, 

 until it looks little different from the surrounding ground. Elis also 

 knows how to practice local mimicry ! 



When one of these mother wasps had retired, the observer dug up 

 the paralyzed spider, which was about four inches below the surface, and 

 found an egg sticking in the body. This egg hatches into a white grub 



