34 -^^i ^'(ils Entomological Society of A merica [Vol .III. 



Avas no perforation over the lly, a small mite was ohser\-ed crawl- 

 ing over the dead body of the fly. 



Placing the bodies of several of these flies under the micro- 

 scope and using a J -inch objective and a No. 5 eye-piece, it was 

 found that on nearly all flies over which the wall was intact, a 

 small mite could be detected, these mites var>'ing in number from 

 two to four mites to each fly. Upon furthering the observations 

 it was found that the dermatitis lasted after the flies had been 

 observed and exterminated. 



The following experiments were tried to pro\e whether it 

 might be the fly or the mite that was the etiologic factor in pro- 

 ducing the deiTnatitis. 



Six live flies were taken, upon which no mites could be found; 

 these were placed under a watch glass and bound upon the right 

 arm, leaving them in contact with the skin for three hours. Upon 

 the left arm four dead flies, on which living mites had been ob- 

 served, were placed under a watch glass and left in contact with 

 the skin for three hours, after which the glasses were rcmo\-ed 

 and results awaited. The right arm showed nothing. Upon 

 the left arm there appeared within twelve hours four small 

 wheals, the character and evolution of which are later described. 



To further the experiments some fresh lesions of patients were 

 scraped and the scrapings examined microscopically and two of 

 the mites were found in the scrapings. 



Itching is the most prevalent and first symptom to attract 

 the attention of the patient. It is most persistent and intense 

 during the after part of the night. At about the time the itch- 

 ing was most intense there appeared an urticarial eruption, 

 accompanied, in severe cases, with general systemic symptoms, 

 such as rise of temperature from 99 to 102; in one case the tem- 

 perature rose to 103.8; the pulse rate is accelerated to 100, or as 

 high as no — in one case to 130. Other symptoms were intense 

 headache, anorexia, nausea, in some cases vomiting, and a mild 

 form of diarrhoea. In severe cases some complained of general 

 joint pains and l)ackachc; in these cases the urine was examined 

 and all)umin in small amount was found, but no casts or blood. 

 When the acute symptoms disappeared so did the albumin. 



Many patients who suffered from mild cases complained of 

 nothing aside from the intense itching. If all straw was remo\'ed 

 from the beds and house the symptoms would subside in one or 

 two days and completely disappear in a few days more. 



