30 Annals Entomological Society of America [Vol. Ill, 



tered into the mattresses, from the use of which came the epi- 

 demic in and about Philadelphia. 



In order to settle these points, Mr. \\ L. Wildermuth, an as- 

 sistant in the Bureau of Entomology', in cereal and forage insect 

 investigations, was instructed to examine the straw in the mat- 

 tress placed at my disposal b\- Dr. Goldberger. After a day and 

 a half of careful search, only five straws affected by the joint 

 worm were found. This seemed to entirely eliminate this species 

 from consideration in connection with this particular epidemic. 

 There were, however, many wheat heads remaining attached 

 to the straw -and these heads contained a great many kernels, the 

 contents of which had been eaten out by the larvae of the grain 

 moth. ]\Iorever, these eaten kernels contained great numbers 

 of the dead bodies of Pediculoides. That Sitotroga cerealella 

 was the cause of this damage to the wheat was still further proven 

 by the emergence of an adult moth from these eaten kernels on 

 November 15. The larvae of this moth infested the kernels of 

 wheat before the latter were threshed. Many of these infested 

 kernels remaining in the straw were included in the material 

 going into the manufacture of these mattresses. The greater 

 portion of the lixing larvae of the moth would develop to adults 

 during May or early June, thus cutting off the food supply of these 

 mites. The mites would therefore very naturally swarm among 

 the straw and making their way through the cloth covering of 

 these mattresses attack anything that gave promise of furnishing 

 food, and preserving them from starvation. It seems that star- 

 vation is the final outcome, however, for, as already stated, no 

 trouble is experienced in using the mattresses after a certain per- 

 iod, which period probably indicates the termination of the life 

 of the mites infesting the straw. It therefore did not seem neces- 

 sary to seek farther for the primary cause of this eastern epidemic 

 of dermatitis, the center of which seems to have been in and about 

 Philadelj)hia. 



A Westerx Epidemic of the Dermatitis. 



While the problem of the epidemic in the east was aj^parently 

 soh'cd, some of the wheat straw involved therein had come from 

 Indiana, and during the last few years an outbreak of the joint 

 worm, Isosoma tritici, had been gathering force, throughout Ohio, 

 Indiana and southern Illinois, until during the summer of 1908, 

 very serious damages occurred. In\estigation of the insect dur- 



