318 NATURE-STUDY REVIEW [15:6— Nov., 1919 



and many orchids: even the characteristic northern gnats and 

 mosquitoes are present to complete the illusion. Then you may 

 fine nearby on the older black oak dune beds of cactus {Opuntia 

 Rafivesque) and the little six-lined lizard both reminiscent of south- 

 ern desert areas. 



One of the most interesting animals of the region is the burrowing 

 spider, Geolycosa pikei, the subject of this sketch. He is a good 

 sized sand colored spider that digs a vertical shaft in the ground 

 in which he hides by day. These are located usually on the open 

 dunes though not infrequently they are found on the oak covered 

 dunes. A good sized specimen of the spider, (Fig. 2,) with legs 

 extended will cover the palm of the hand. His coloration is so 

 exactly that of the sand that one scarcely sees him until he moves. 

 He hunts in the dusk, running rapidly over the sand to find stray 

 insects upon which he may pounce. On quiet mornings when the 

 sand is not drifting, the surface of the dune near the spider's hole 

 is covered with the telltale tracks of the night's hunting trips 

 and these often run many rods from his retreat. 



Dtiring the glare of the day he remains in his hole unless some 

 unwary insect comes near enough to be captured without undue 

 exposure. The hole varies in diameter and depth with the size 

 of the animal, being only as large as a knitting needle in the case 

 of the baby spider but three quarters of an inch or so in diameter 

 for the full grown animal. (Fig. 3.) The hole sometimes extends 

 down into the moist cool sand a distance of two feet, though 

 the average for the mature spiders is probably not over eight or ten 

 inches. While the sand of the dunes appears very dry it is only 

 necessary to scrape away the top two or three inches to get down 

 to the moist and firm sand. Naturally the dry surface sand is 

 very unstable and the spider's hole would speedily cave in were 

 it not for the fact that he spins a silken lining for the upper two 

 or three inches. (Fig. 4.) 



The digging and the deepening of the hole is commonly accom- 

 plished at night. Often in the early morning the holes are sur- 

 rounded by little dabs of moist sand that are then conspicuous 

 on the lighter colored dry surface. These have been thrown out 

 by the spider in the process of excavation. (Fig. 5.) You may catch 

 the digger at this occupation ; then as you stand watching the hole 

 there shoots out a little mass of sand, a minature volcanic eruption. 

 Close observation shows the spider near the opening and appar- 

 ently he hurls the sand out by a quick movement oi his palps. 



