30 MONTANA EXPERIMENT STATION BULLETIN 474 



The reasons for this winter population increase are not as 

 yet completely clear. Both the usual poor condition of the cattle 

 in a severe winter and the possibility of a more desirable habitat 

 for the lice must be taken into consideration. Fall spray treat- 

 ments with lindane have successfully prevented severe louse 

 buildups in the winter and early spring and their resulting detri- 

 mental effects to cattle. 



SHEEP TICKS (Melophagus ovinus) 



Sheep ticks are common in all of the sheep raising areas of 

 the state, and often cause considerable damage. Excellent control 

 has been obtained with rotenone dips and spra\^s. 



HORN FLIES (Siphona irritans) 



Horn flies generally occur throughout the state, and when un- 

 controlled cause considerable weight reductions to cattle. The use 

 of methoxychlor sprays on dairy cattle and DDT sprays on range 

 cattle have successfully provided economic control of this insect. 



MINK MAGGOTS (Wohlfahrtia opaca) 



Several cases in Gallatin County of primary myiasis occurred 

 in the summer of 1950 on small pups which for the most part were 

 from two to four weeks of age. Only one case of this myiasis is 

 known to have occurred on an adult dog. No cases of myiasis on 

 mink were reported. 



MISCELLANEOUS INSECTS 



GRASSHOPPER MITES (Trombidiidae Family) 



Numerous inquiries concerning Tromhidium mite parasites on 

 grasshoppers were received in 1950. This is a rather common con- 

 dition and is not known to be an important factor in the reduction 

 of grasshopper populations. 



SUN SPIDERS (Solpugida Order) 



Sun spider specimens were received for identification from 

 Daniels County in 1949 and Lewis and Clark and Cascade counties 

 in 1950. This ferocious appearing arachnid is primarily a nocturnal 

 predator of insects and other arachnids. 



CHOKE CHERRY MIDGE (Contarinia virginianiae) 



The orange to pink colored larvae of the choke cherry midge 

 feed inside of the choke cherry, causing swollen deformed cher- 

 ries. This insect occurs commonly throughout Montana and was 

 reported in Park, Flathead, Lake, and Lewis and Clark counties 

 during the biennium. 



