I think their mother's name is Eliza or Elizabeth PUGH; I found this 1900 IA census that seems to match for the boys but the mother's place of birth is Ohio.

Source Citation: Year: 1900; Census Place: Center, Madison, Iowa; Roll: T623 445; Page: 14A; Enumeration District: 21.; taken June 11/12?, lines 31-34, 328/339, on Jefferson street, Winternet(sp) city
Name: Walter W Wright
Home in 1900: Center, Madison, Iowa
Age: 13
Estimated Birth Year: abt 1887
Birthplace: Kansas
Relationship to head-of-house: Son
Parent's Name: Eliza J
Race: White
Occupation: View image
Neighbors: View others on page
Household Members: Name Age
Eliza J Wright 52y,[c1848] h/h, w, f, b.Mch 1848, Wid, 6 births/4 living, OH OH PA, owns home w/mortgage,
Charles W Wright 24y,[c1876] son, w, m, b.Aug.1875, sngl, NE VA OH, Salesman/Pam??
Myrtle M Wright 18y,[c1882] dau, w, f, b.June 1881, sngl, NE VA OH, Domestic servant
* Walter W Wright 13y, son, w, m, b.Feb.1887, sngl, KS VA OH, at school

And also Charles is listed as b.NE so that might make some confussion too.

I found these in the CA death index, which might indicate that Eliza's maiden name was PUGH; I haven't looked for her in 1870 yet to see if I could find a match.

WRIGHT WALTER W 1887 02 21 mmn/PUGH MALE b/KA d/SANTA CRUZ 1968 10 21 567308372 81yr

? maybe Walter's wife; remarried after Walter died;
EAKER PHYLLIS E 1907 11 07 mmn/DYER fa/ADDICOTT FEMALE b/CA d/SANTA CRUZ 1998 01 12 571260625 90yr

I will look some more. Nanc