ENTOMOLOGY

MYIASIS-ITS PREVENTION AND TREATMENT 207producing pure water. Where it is essential that water must be takenfrom streams care should be exercised not to drink near vegetation.Use of Screena.-Proper screening of houses will do much to protectfoods after prcparation from infestation, although some of the smallforms can not be kept out in this way. A coarser mesh than 16 per inchshould not be used. The use of screened toilets of course can not be toostrongly emphasized.Clea'1llmess and CarefUl Habits.-Many infestations of thc digestivesystem and genitalia could be avoided by not sleeping in unscreened placesin an exposed condition. Prompt attention to infants is important.SPECIES INFESTING HEAD PASSAGESInfestations in A'1limals.-The parasitic forms are very difficult tocontrol and no very satisfactory control measures have been devised.Nearly all of the recommendations made are of little value. Some ofthese consist of the use of repellents in the case of sheep to protectthem from infestation by Oestrus ovis. Pine tar is most frequently usedand this is applied by the sheep themselves. Holes in logs are used forsalting and the sides are smeared with tar. The provision of plowedfurrows where the sheep can protect their noses probably gives somerelief. For very valuable animals screened pens are no doubt warranted,the animals being placed in these during the portion of the day whenthe flies are most active. There seems to be considerable difference ineffect of attacks on breeds. Attempts to remove the larvre from the noseby causing sneezing or with fum~gants arc more likely to drive the larvredeeply into the head than to remove them. Trephining the skull andremoving the larvre in that way may give some relief but is usually notadvisable as other infestations are likely to follow and all the grubscan not be reached. Destruction of adults has been advocated and is.especially applicable to plains areas, as in such places flies are inclinedto congregate on any objects which extend well above the ground. Theflies assemble on such objects and remain there except during the wannerpart of the day and many can be killed.Many of the control measures suggested for the control of the sheepbot can be used against the horse infesting species, Rlzinoestrua purpureua.It might also be possible to utilize muzzles similar to those advocatedfor the horse bots to protect against infestations from this species.Infestations in i1Ian.-lnfestations of man arc so infrequent that preventivemeasures need receive little attention. "Yhere such infestationseither by the sheep head maggot or horse head maggot are commonthe use of nets on the hats similar to those used by apiarists wouldgive protection. Medical attention should be given promptly for re-~ moval of larvre, especially if in the eye.