30 DEPARTMENTAL REPORTS. 



parts of the country, but from iiiauy different parts of the world, and 

 tile knowledge thus gained can not fail to be of substantial practical 

 value. 



INSECTS AS CARRIERS OF DISEASE. 



This subject, also referred to in the last report, has been studied 

 through the year — entirely, however, from the entomological and not 

 from the medical side. The mosquitoes of the genus Anopheles (the 

 only genus v.hich has been shown to be instrumental in the spread of 

 malaria) ha\ e been studied with special care. The full biology has 

 been learned, illustrations of all different stages have been made, and 

 many experiments on remedies have been carried out. The Ento- 

 mologist has addressed several organizations which have been taking 

 up the subject of mosquito extermination, and at the request of the 

 American Medical Association lectured on the life history of the 

 nuxlaria-bearing forms before its section on theory and practice of medi- 

 cine at its annual convention held in June, 1900. He has also been 

 able to j)oint out in several instances the breeding places of Anopheles 

 in malarial regions, and to advise as to their abolition. The insect 

 fauna of human excrement has received constant attention on account 

 of the reasonably certain relations between such insects and typhoid 

 fever, as well as other diseases of the intestinal tract. The results of 

 the mosquito studies have been published in Bulletin No. 25, new 

 series, and the results of the second line of work are now being pre- 

 pared for publication. 



WORK ON INJURIOUS GRASSHOPPERS. 



In the summer of 1899, as in previous j^ears, a special field agent was 

 authorized to visit x)ortions of North Dakota and Manitoba for the pur- 

 pose of investigating a supposed permanent breeding ground of the old 

 Rock}' Mountain locust, or Western grasshopper, in the Turtle Moun- 

 tain region. Careful investigation showed that the species in ques- 

 tion does not breed permanently in the Turtle Mountains nor in their 

 immediate vicinity. Tiie ground is totallj' unsuited to the purpose, 

 and, moreover, swarms descending upon North Dakota and ^Manitoba 

 have been traced far to the northwest of that region. The probable 

 permanent breeding ground, according to the special agent (Mr. W. 

 D. Hunter), is upon the Assinniboine River, north and east of Regina, 

 in ihe territory of Assiniboia. This conclusion demands serious 

 investigation on the part of Canadian authorities, and the Entomolo- 

 gist has ctuTcsponded with the Government Entomologist of Canada 

 in this regard. In the la.st report it was predicted that damage from 

 the local swarms which were reported in North Dakota in 1898 (a 

 return migration fi-om the* South Dakota swarm of 1895) would pro- 

 duce little damage during 1899, a prediction Mhich was verified to a 

 degree. There was a local visitation of grasshoppers in North Dakota, 

 but the county authorities took the matter in hand. 



Considerable damage was done during the summer of 1899 by local 

 species of grasshoppers in portions of Colorado and Mississippi, as 

 well as at one locality in Alabama. This damage was repeated to a 

 certain extent during the summer of 1900 in Colorado and Mississippi. 

 The Mississippi outbreak threatened to be an especially serious one. 

 Large cotton interests in Bolivar County were threatened by enor- 

 mous numliers of the species knoAvn as AManoplua dijfereiiiiaUs and 

 one or two less prominent species. An agent Avas sent to this locality 



