72 DIPTERA OF MINNESOTA. 



where these pests abound. Countless other instances might be cited 

 of man's inabiHty to cope successfully with this tiny fly. It is not 

 only a northern production, occurring often in Iceland, but is 

 also found in the tropics of Africa and America. Through the 

 southern part of the United States they are referred to as "Turkey 

 Gnats" or "Sand Flies," and they sometimes cause very serious losses 

 among stock, a fact which has already been referred to. The death 

 of the afflicted animals is thought to be due to a poison left in the 

 wound by the fly, said poison producing a disease which causes death 

 very shortly. In 1884, in Franklin Parish, Louisiana, they killed 300 

 head of stock in a week. In 1874 the State of Tennessee alone 

 lost as much as $500,000 worth of stock from attacks of these flies. 

 Referring to their abundance in the South Dr. Lugger says, in one 

 of his reports: "Nobody can realize the beauty of southern scenery 

 who has not been there during plowing time and when the buffalo 

 gnats were out in force. Just imagine a mule coated with stinking 

 oil, or painted with mud or molasses, pulling a plow from which is 

 suspended a tin pail containing a smudge, while the mule is further 

 adorned by another tin pail suspended from his neck; the latter con- 

 tains also glowing embers in which are produced such fine odors as 

 can be made by burning leather and other similar substances." We 

 have found S. venustum, fairly abundant and annoying stock in this 

 State about the last of May (27th-30th). 



My predecessor, in working up Minnesota forms, was evidently, 

 according to his labels and his report for 1896, led into error, and mul- 

 tiplied the number of species occurring here. In other words, out of 

 S. venustum he created S. irritatum, and S. miniitum, and wrongly 

 identified some specimens of S. vemistiim as S. decorum, Walker. This 

 mistake was evidently first suspected by O. A. Johannsen of Ithaca, 

 New York, and has been the subject of considerable correspondence be- 

 tween him and the writer. He has kindly cleared up the tangle, and un- 

 hesitatingly pronounces Lugger's specimens (imagoes) of S. irritatum, 

 S. decorum and S. minutum to be S. venustum. His (Lugger's) S. 

 tribulatum is S. vittatum. Therefore, in his Second Annual Report, 

 1896, Fig. 143 should be labeled S. venustum and not S. minutum; 

 Fig. 144 is the same, not decorupi; Fig. 145 is not irritatum, but 

 venustum, as is Fig. 146, which Lugger also called irritatum. Fig. 

 147 on page 179 of his report is the larva of S. vittatum, not tribulatum, 



