I found the following children living with their grandmother at Automated Genealogy
1901 Canadian Census ON DURHAM (West/Ouest) Cartwright b-2 1 19
195 McQuaid Liettia FHead W Aug 15 1830 70 205 McQuaid Wilbert P MGrandson S Apr 20 1888 13 215 McQuaid Harold MGrandson S Nov 6 1890 11 225 McQuaid Roy MGrandson S Oct 5 1892 9 235 McQuaid Margret FGranddaughter S Apr 5 1894 6 http://automatedgenealogy.com/census/index.htmlhttp://automatedgenealogy.com/census/index.html
You can view the original 1901 Canadian Census pages at the above address or at the Library and Archives Canada's 1901 Canadian Census Returns at http://www.collectionscanada.ca/02/020122_e.htmlhttp://www.collectionscanada.ca/02/020122_e.html
Here is Letitia in the 1881 Canadian Census with her husband: Thomas MC QUAIDEMaleIrish21OntarioFarmerMethodist Canada Letitia MC QUAIDEWFemaleIrish47OntarioMethodist Canada Source Information: Census Place Cartwright, Durham West, Ontario Family History Library Film1375878 NA Film NumberC-13242 District128 Sub-districtD Division1 Page Number25 Household Number103 There are also other McQuaid in Cartwright Township. You can search the index at http://www.familysearch.org/Eng/Search/frameset_search.asp?PAGE=census/search_census.asphttp://www.familysearch.org/Eng/Search/frameset_search.asp?PAGE=census/search_census.asp
Perhaps you may be able to find more about the family at the Ontario Vital Statistics Project at http://www.rootsweb.com/~onvsr/http://www.rootsweb.com/~onvsr/ .