much as fourteen inches away, or atop a fly that set- 

 tles within a comparable distance. Jumping spiders 

 use their eyes also in following a complicated code of 

 semaphore-like signals through which the males seek 

 to excite a female into permitting an approach. 



Other arachnids probably depend far less upon 

 vision, although elaborate claims have been made. 

 For a while it was believed that the white crab spi- 

 ders found on white daisies in midsummer would 

 change color to a butter yellow within a few days if 

 transferred to a yellow flower. But this camouflage 

 seems fortuitous. Crab spiders are white in midsum- 

 mer and yellow in autumn, whether on white flowers 

 or on yellow ones. They change hue gradually, and 

 happen to match a common sequence in flower col- 

 ors. That they often match the flower upon which 

 they crouch while waiting for an insect to visit and be 

 caught may be helpful in concealing them from spi- 

 der-eating birds. But insect victims are unlikely to 

 detect the waiting spider in a flower so long as the 

 spider remains motionless until its prey is within 

 snatching distance. 



SOLPUGIDS 



A constriction between the cephalothorax and the 

 abdomen is obvious also in the spider-like solpugids 

 or "false spiders" (order Solpugida) of tropical and 

 subtropical countries. The solpugid abdomen, how- 

 ever, is clearly segmented. 



Solpugids are harmless, for they lack venom, de- 

 pending upon crushing insect prey between the for- 

 midable-appearing fangless chelicerae. For the most 

 part, solpugids are denizens of arid lands, venturing 

 out at night. They range in size from barely more 

 than Vi of an inch in length to nearly 3 inches. They 

 run nimbly and will defend themselves if disturbed. 

 At such times the solpugid is seen to be using three 

 pairs of legs in locomotion and holding free of the 

 ground the front pair, as well as the leglike but pin- 

 cer-tipped pedipalps. 



SCORPIONS 



A true scorpion (order Scorpionida) is obviously 

 segmented, the head bearing chelicerae suggesting 

 lobster claws, the thorax of four segments each with a 

 pair of walking legs on the undersurface, and the 

 segmented abdomen broad in front but tapering to a 

 more cylindrical portion that ends in a curved, poison- 

 injecting sting. Scorpions are largely nocturnal, hiding 

 under rubbish during the day or remaining in little 

 holes dug with the pincer-tipped chelicerae. 



In ancient times, a scorpion was feared almost as 

 much as a lion. Both are among the animals repre- 

 sented in the zodiac — constellations of stars in the 

 band of sky through which the sun, moon, and plan- 

 ets seem to move. Scorpio, one genus of scorpions, is 

 thus the astrologic birth sign for people born in the 



Some larger, thinner huntsman spiders are welcomed 

 in tropical and subtropical homes as the answer to 

 flies, roaches, and other household insects. This one, 

 Heleropoda lenntoria, on the wallpaper of a Florida 

 home, has a .'}-inch span. (Lorus and Margery Milne) 



A wolf spider, its feet clothed in water-repellent hairs, 

 can run dryshod over the surface of ponds and streams. 

 ( Herman Eisenbeiss ) 



