brown and spherical and have been considered by some earl}^ writers as 

 fungi. The chlorion or outer skin splits soon after the eg-g-s are deposited, 

 dividing the eggs into halves and exposing the pale vitteline membrane. 

 The larva when hatched is circular or ovoid in outline, and each of its 

 three pairs of legs is tipped with two or three prominent claws. After 

 the larva has become attached to its insect host it elongates and becomes 

 swollen with food. When full fed it drops off, seeks a convenient shel- 

 ter, and gradually changes in shape without molting. The new parts 

 are formed under the larval skin, which after a few weeks cracks and 

 discloses the adult Trombidiuni. The mature harvest mite is preda- 

 ceous, wandering about and feeding on aphides, small caterpillars, and, 

 in the case of one species, on the eggs of grasshoppers or locusts. It 

 hibernates in the soil or in other sheltered locations and in the spring 

 deposits its eggs. There appears to be a single generation produced 

 each j^ear. Only a few forms have been reared. The larva of one 

 occurs commonly on the house fly in autumn. 



REMEDIES. 



Preventive. — As harvest-mite infestation is usuall}^ contracted by 

 walking or working among l)lackberrv and other shrubbery which har- 

 bors them, or by walking, sitting, or lying among grasses or similar 

 herbage along streams or pools on the edges of marshes or under trees 

 near such places, it is obvious that the best means of prevention is the 

 avoidance of exposure by susceptible persons. If, however, a bath is 

 taken in hot water, or water containing salt or strong soap, within a 

 few hours after exposure, no ill effects will be experienced. After a 

 longer exposure a bath has practically no effect, and direct remedies 

 are necesssary. 



Sulphur is a sovereign remedy for mites and is the best preventive of 

 attack. When exposure is unavoidable and where vegetation is not 

 more than 2 or 3 feet high, a sure preventive is found in sifting ffowers 

 of sulphur into the underclothes from a little above the knee downward 

 and into the shoes and stockings, or it may be rubbed over legs and 

 ankles. Naphthaline has been successfully used in the same manner in 

 Mexico by Dr. L. O. Howard and in Cuba by Mr. E. A. Schwarz. 

 While the sulphur, being inodorous and perfectly effective, is undoubt- 

 edly preferable against harvest mites alone, naphthaline is a safeguard 

 against various forms of man-infesting tropical insect pests. Vaseline, 

 pure or mixed with sulpiuir, will serve the same purpose. l)ut is not so 

 agreeable on account of its oily nature and the certainty of its soiling 

 the clothing. 



For most localities these precautions are to be observed through the 

 months of July, August, and a part of September. The mites are sel- 

 dom bothersome in early June or as late as October, but in exception- 

 ally warm seasons they arc apt to be encountered in both months. 



[Cir 77] 



