224 AMERICAN SPIDERS 



The best-known giant crab spider is Heteropoda venatoria 

 (Plate 10), the huntsman spider, a species that occurs around the 

 world in the tropical zones, and penetrates northward into Florida, 

 where it is quite common, and into the subtropical regions of Texas 

 and California. This spider probably came originally from the 

 Asiatic mainland, where many close relatives live and from which 

 locality we have acquired many of our commonest domestic in- 

 sects. It was the belief of Henry McCook that the huntsman was 

 distributed by means of ballooning threads, and that its tropico- 

 politan distribution was determined by the prevailing trade winds. 

 This may be partially true, since it is known that flyng spiders 

 cover tremendous distances, but its prevalence can be attributed 

 also to a great climatic tolerance, and to domestic habits that made 

 it an ideal emigrant in goods carried by boat. None of the close 

 relatives of the huntsman spider has been disseminated in a like 

 manner, even though the habits of the species are similar and the 

 opportunity for transfer was present almost equally to all of them. 



Often having tawny bodies over an inch long and outspread legs 

 spanning three or more inches, the huntsmen are the commonest 

 and best known of tropical house spiders. They are generally wel- 

 come because of their depredations on roaches and other disagree- 

 able insects that abound in the poorly constructed homes of the 

 tropics. Although they also live under bark and in similar situations 

 in the open, they show a marked preference for houses, barns, 

 docks, sheds, and other buildings of man. Hidden away in crevices 

 by day, they come out at night and hunt or sit on the walls. Be- 

 cause they frequently are carried into northern regions in banana 

 bunches, Heteropoda venatoria is often called the "banana spider." 

 Some of the species of Selenops are also domestic and equally wel- 

 come in houses. In Panama one kind lady showed the author sev- 

 eral of these flat creatures sitting on the walls of her kitchen, knew 

 the location of everyone in her establishment, and praised them as 

 being very beneficial. 



The typical crab spiders of the family Thomisidae rarely exceed 

 one-third inch in body length. Frequently occurring in abundance, 

 conspicuous because of their bright coloration, the approximately 

 two hundred species found within the limits of the United States 

 are encountered as commonly in the north as in the south. These 

 most highly developed of all laterigrade spiders have become spe- 

 cialists in ambush; they accomplish by surprise what the jumping 

 spider is able to achieve through superlative eyesight and stealthy 

 approach. Fortified with extremely potent venom, presumably in 



