530 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



souri. Curiously enough, another problem has entered into the joint- 

 worm investigation, which involves sanitary as well as agricultural 

 matters. A mite known as Pediculoides vcntricosus attacks both the 

 jointworm and its hymenopterous parasites, and by its work upon the 

 parasites prevents them from overcoming the jointworm. The mite 

 remains in the straw up to and during the early summer following the 

 harvest, and, whether this straw goes into the manufacture of mat- 

 tresses or whether it enters into the domestic economy of the farm, it 

 invariably causes a very annoying skin disorder, recently designated 

 by Doctor Goldberger as Der-Tnatitis schamhergi. Throughout the 

 Middle West the jointworm is the host of this mite, but the mite has 

 caused equally serious trouble in eastern Pennsylvania, New Jersey, 

 Delaware, Maryland, and Tennessee. Throughout this last territory 

 the host insect is the Angoumois grain moth. In both cases it appears 

 that a revision of certain agricultural methods will become necessary. 

 The farmer throughout the Middle West and in the East draws the 

 unthrashed grain in from the fields, places it in barns, and allows 

 it to remain unthrashed for weeks, and sometimes perhaps even for 

 months. This facilitates the development and increase of the mite, 

 and causes an increased number of cases of dermatitis. In Tennessee 

 the farmers allow the grain to remain in the shock long after it 

 should have been thrashed. This also facilitates the increase of the 

 mite, with the result that when this grain is thrashed the men and 

 teams engaged in the work are attacked and caused great pain and 

 suffering. In all cases, if the wheat is thrashed directly from the 

 field and as soon after harvest as it is in condition for thrashing 

 much of the difficulty will be overcome. 



HESSIAN FLY INVESTIGATIONS. 



The investigations of the Hessian fly have been continued, and 

 a successful introduction of parasites from Kansas has been made 

 into the wheat section of western Oregon. It now seems quite possi- 

 ble as the result of the investigations of the year that what was 

 supposed to be winter-killed wheat in Oregon has really been the work 

 of the Hessian fly. In recent years farmers have found it imprac- 

 ticable to grow wheat in western Washington and Oregon on this 

 account. The attacks of the Hessian fly in the fall have produced 

 this result, and the successful introduction of eastern parasites 

 should have a beneficial effect. 



An unexpected outbreak of the Hessian fly in Tennessee is being 

 investigated in cooperation with the agricultural experiment station 

 of that State. 



Up to the present time it has been impossible to secure absolute 

 proof that the Hessian fly will attack grasses, but it has been ascer- 

 tained during the year that it attacks one or more species of Agro- 

 pyron both in Kansas and in western Washington. To what extent 

 this phase of the problem will increase in the future it is impossible 

 to predict, but it will have the effect of allowing parasites to breed 

 in grass affected by the Hessian fly and to migrate to wheat fields 

 and attack the host insect there. 



THE NEW MEXICO RANGE CATERPILLAR. 



The unusual and serious state of affairs caused in northeastern 

 New Mexico by the sudden extraordinary development of the larva 



