iQio] Pediculoides Noxious to Man 



ZZ 



Rawles' investigations were very carefully made and the results 

 are exceedingly valuable for the reason that, in case of this western 

 epidemic, he was able to trace the cause of the dermatitis to 

 Pediculoides ventricosus and follow this back to the host insect 

 Isosoma tritici. This paper of Dr. Rawles^^ of which a summary 

 is given, not only clears up the obscurity with reference to the 

 cause of this epidemic in the Middle West, a section throughout 

 which the grain moth (Sitotroga cerealella) never occurs in exces- 

 sive abundance excepting in grain that is kept in store, and 

 then only in the more southern portions of Indiana and Illinois ; 

 but, furthermore, these studies seem to solve the problem of the 

 cause of the skin eruption noted by Dr. Harris to have occurred as 

 far back as 1830. 



In May, 1909, Dr. Rawles found in his practice that a very 

 strikingly strange skin disease presented itself in his and sur- 

 rounding country in epidemic form. Through the press notes it 

 seemed to be quite general over the northern part of the United 

 States, limiting itself to the wheat growing sections. 



The people generally affected were farmers and those living 

 in small villages or towns where straw is used in beds, under car- 

 pets and around stables to bed stock. Horses and cattle have 

 been seen with a skin disease almost identical to that seen in man. 

 The following incident led him to an investigation as to the prob- 

 able etiology: 



A family had cleaned house, refilling the straw ticks of their 

 beds and placed fresh straw under the carpets, and in about one 

 week the family had developed this peculiar skin disease. In the 

 beds were found a small, black fly, Isosoma tritici Fitch, about 

 the size of an ordinary gnat, which at first it appeared to be, but 

 closer observation revealed that it was not of the gnat famil^r. 

 Upon examination of the straw it was found that a large number 

 of the straws were perforated; these perforations were through 

 the wall in the region of the joint, generally about two inches 

 from the joint. The perforations were about the size of a small 

 pinhole and ranging in number from ten to thirty in a straw. 

 Upon examining a section of this straw the small black fly was 

 found under many of the openings through the walls. 



Several flies were examined to ascertain if they possessed a 

 piercing proboscus, and while observing one which has just been 

 taken from under the sheath of the straw, through which there 



13. Journal of the Indiana State Medical Association, August, 1909. 



