66 MTSCEf.LANEOrS NOTES ON ECONOMIC WORK 



Tlu- hilinj;- stable Hy. a close relative of the hottse tlv. but a 

 bi(j()(l-suckin^- insect, is a serious pest of stock in Minnesota. Some 

 time has been given to studying- it under local conditions. Its life 

 history is in g-eneral like that of the ht)use i\}\ l)reediny principally 

 in stal)le manure. Control measures are similar. ( )ur next search 

 will be tor a good repellant which may be applied to animals to 

 prevent its attack when breeding cannot ])e controlled. At present 

 there is no material on the market for this purpose, which is sufh- 

 ciently cheaj). or elTective when ai)plied. The relation of this insect 

 to swamp-fe\er of horses has also been under investigation, but 

 will be re])orted upon elsewhere, as the work was done under a 

 different fund. 



Horse Hies are, next to mosquitoes, the worst pest of stock in 

 the northern part of ^Minnesota. Funds ha\e not made it possible 

 for us to carry on as intensive a study of these insects as they 

 deser\e. In places where farmers are trying to build up dairy 

 farms, the presence of these flies has reduced the milk supply as 

 much as (>() per cent in two weeks and in three nearly 100 per cent. 

 There is also a \ery large, l)Ut not easily recognized, insidious loss 

 to animals from the annoyance caused by these flies and the result- 

 ing nervous reacticm, as well as by the loss of blood, for the^• are 

 possessed of very large, piercing mouth parts and blood may flow 

 from the wound for a long time after they have filled themselves and 

 flown away. There is only one generation each year, the adidts 

 appearing" in spring and early summer in enormous niunbers, dis- 

 appearing in about four weeks. Five species are common in the 

 northern ])art (.)i the state. These seem to breetl in low-lying, wet 

 land surrounding swamps and muskegs, it reciuiring ten to eleven 

 months for the growth of the grul) in these wet ])laces. PVobably 

 more extensive cidtivation and drainage will reduce the numbers 

 of the flies by removing their breeding places, but further studies 

 of these flies must be made as soon as funds are available, before 

 aulhoritatixe recommendations can be made. The connection of 

 these flies with swamp-fever has also been investigated. 



There is a growing demand for more information ujjon mos- 

 qtiitoes, mostly from the cities, l)ut also from farming districts. 

 While a quite complete survey for species foimd in Minnesota was 

 made several vears ago, our knowledge of these insects has increased 

 verv much in recent years and a new survey has l)een l~tegun, not 

 only to ascertain the kinds of mosc|uitoes occurring in the state, but 

 also their habits and life histories. This survev is now well under 



