living in the hair follicles, cause mange in many 

 kinds of mammals. 



Beekeepers are familiar with Isle of Wight dis- 

 ease, a fatal epidemic in hives of cultivated bees that 

 become infected with a mite that invades their 

 tracheae and suffocates the insects. 



The pest known as "red spider" in gardens and 

 orchards is actually a vegetarian mite. Severe infes- 

 tations can be recognized from the loose webs cover- 

 ing leaves upon which the female mites have laid 

 their eggs. Other mites attacking plants cause cancer- 

 like growths of characteristic forms, each known as a 

 plant gall. 



Ticks have an equally bad reputation for transfer- 

 ring diseases from one animal to another. Texas cat- 

 tle fever is an infection of the sporozoan (a proto- 

 zoan) Babesia bigemina, transmitted by the tick 

 Margaropiis anmilatiis. The larvae, called "seed 

 ticks," are about 'i.^ of an inch in length. After gorg- 

 ing themselves on blood, they drop off the steer and 

 transform into slightly larger, eight-legged nymphs. 

 Soon they again climb a grass blade and catch a pass- 

 ing animal. After gorging again, the nymphal tick 

 drops off and matures to the adult, either a "m-inch 

 male with an oval brown body, or a i^-inch female 



of rectangular outline, whose color may be yellowish 

 to slate gray. These adults again seek a steer and 

 mate upon its back after another blood meal. The fe- 

 male then drops off and layers her five thousand eggs 

 on the ground, where they hatch, starting another 

 generation of seed ticks on its way. 



Rocky Mountain spotted fever is a rickettsia dis- 

 ease transmitted by the widespread tick Dermacen- 

 tor, a parasite found commonly on dogs. It attacks 

 coyotes and many other wild animals in the western 

 United States. Some of these are reservoirs of infec- 

 tion for spotted fever. If an infected tick bites a hu- 

 man being, the person is almost certain to contract 

 the disease. If proper medical care is not given, the 

 outcome can be serious or even fatal. 



The Sea Spiders 



( Class Pycnogonida ) 



A skin diver who sits quietly watching a clump of 

 kelp, a sea fan, or a coral head may well discover a 

 spider-like creature moving with the utmost deliber- 

 ation among these. Sea spiders mostly possess four 

 pairs of very long legs, each pair arising from a sepa- 



Harvestmen are seen most often at harvest time. Their widespread legs well earn them the 

 name "daddy-long-legs." (Colorado. Walker Van Riper) 



