82 



ECONOMIC ZOOLOGY 



"The spiders of the genus Latrodectus, of which we have a common 

 representative in the South, are feared wherever they occur, and it is 

 quite possible they are more venomous than other spiders." 



Scorpions, Fig. 61. These curious and dreaded animals with the 

 "sting" at the end of the tail are often abundant in tropical and sub- 

 tropical countries. The sting of a large zo-inch specimen may be seri- 

 ous; that of an ordinary 3- or 4-inch animal is 

 usually about as severe as the sting of a wasp or 

 hornet. 



There are several small arachnids, of the 

 order Acarina, that are external parasites on 

 man and other animals and are sometimes a 

 serious pest. For example, the tiny harvest- 

 mites or chiggers burrow into the skin of man 

 and cause most annoying itching; they may be 

 killed by rubbing the skin with kerosene, a i 

 per cent, solution of carbolic acid, or other 

 similar substance. 



Poultry and cattle ticks, Fig. 62, cause in- 

 jury to their hosts, the latter in particular as a 

 carrier of the germ of the Texas cattle fever, as 

 described in connection with the Protozoa. 



The follicle mites, Fig. 62, C, live in the hair 

 follicles and sweat-ducts of man and cause 

 "blackheads;" the itch-mite, Fig. 62, D, by 

 burrowing in the skin produces intense itching, 

 and the sheep-scab mite produces scabs on the 

 skin of sheep, cattle and horses. 



King-crab or horse-shoe crab, Limulus, Fig. 63. This is perhaps 

 the largest of living arachnids, reaching an extreme length of 2 feet. 

 It is one of the few members of this class that live in the sea, where it 

 is found crawling or slowly swmiming over the sand or mud flats along 

 shore. It is interesting zoologically and is said to be fairly good as 

 food, though it is not very commonly eaten. It is sometimes classed 

 with the Crustacea, as its affinities are uncertain. Along the shores 

 of Delaware Bay it is caught by the ton, as it comes ashore to spawn; 

 it is used as food for hogs and as a fertilizer. 



FIG. 61. Scorpion, 

 Centrums sp. X%. 



