If Tobias had been the son of a prior wife, the enumerator may have listed him last in the 1850 census, after Barbara's children.

1.  Marriage Record:

2.  Census Index:  U.S. Selected Counties, 1830 (Broderbund CD-315):  not found.

3.  1840 Census Index and Digital Images (online at Ancestry.com; Image #9 of 14; extracted by Diana Gale Matthiesen):¤•

1840

PA

Union [now Snyder] Co.

Perry [now West Perry] Twp.

p. 390A

Ln. 31

Straub Daniel

010 001 - 210 010

These data indicate:

No. & Sex	Age Class	Therefore Born	Individuals Inferred
1 male	5-9	1830-1835	= Son
1 male	30-39	1800-1810	= Daniel (b. 1807)
2 females	4 or under	1835-1840	= Sarah? (b. 1840/1) = Catharine (b. 1835/6)
1 female	5-9	1830-1835	= Daughter A
1 female	20-29	1810-1820	= Barbara (b. 1804/5)

Barbara appears to be fibbing about her age — not wanting to pass the big three-oh.

4.  1850 Census Index/Images (online at Ancestry.com; Image #19 of 33):  Perry [now West Perry] Twp., Union [now Snyder] Co., PA, p. 107A, 132/132, enumerated 18 Nov 1850 (extracted by Diana Gale Matthiesen):¤•

Daniel Straub	46	M	Cooper	Penna
Barbara Straub	45	F		Penna
Catharine Straub	14	F		Penna
Sarah Straub	9	F		Penna
Susanah Straub	7	F		Penna
Barbara Straub	1	F		Penna
Tobias Straub	20	M	Labourer	Penna

5.  1860 Census Images (online at Ancestry.com; Image #382 of 384):  Richfield P.O., West Perry Township, Snyder Co., PA, p. 674, PN 194, 1384/1444, enumerated 17 Jul 1860 (extracted by Diana Gale Matthiesen):¤•

Daniel Stroup	53	m		Cooper	800	200	PA
Barbara   "	49	f					"
Susannah  "	14	f					"
Barbara   "	11	f					"
Tilman    "	5	m					"
Daniel    "	17	m					"	scarlet fever; deaf & dumb

Daniel was not in their household in 1850, so is he not their son?  But he is treated as a son in 1870 and 1880.  Was he institutionalized in 1850?  Listed next door to John & Susanna (SNYDER) STROUP. 

6.  1870 Census Index/Images (online at Genealogy.com, Image #1 of 16):  Richfield P.O., West Perry Twp., Snyder Co., PA, Roll 1451 (Book 1), p. 204A, PN 1, 7/7, enumerated 6 Aug 1870, official enumeration date 1 Jun 1870 (extracted by Diana Gale Matthiesen):¤•

Stroup Daniel	60	M	W	Cooper	800	200	Pa
"   Barbara	56	F	W				Pa
"   Daniel	26	M	W	Laborer			Pa
"   Tillman	16	M	W				Pa

7.  1880 United States Census and National Index (LDS Family History Resource File: CD-ROM Library):¤•

Census Place: West Perry, Snyder, Pennsylvania
Source: Film 1255194; NARA Film T9-1194; Pg 155C
	Relation	Sex	Marr	Race	Age	Birthplace	Occupation	Fa	Mo
Daniel STROUB	Self	M	M	W	73	PA		PA	PA
Barbara STROUB	Wife	F	M	W	68	PA		PA	PA
Daniel STROUB	Son	M	S	W	37	PA		PA	PA

8.  1890 Census:  the 1890 Census Population Schedules were destroyed.

9.  1900

10.  1910 Census Index/Images (online at Ancestry.com, Image #11 of 15):  West Perry Twp., Snyder Co., PA, Roll 1415, p. 303A, SN 6A, SD 13, ED 159, enumerated 28 Apr 1910, official enumeration date 15 Apr 1910 (extracted by Diana Gale Matthiesen):

1910:  for an explanation of the column headings, please see What the Numbers in the Federal Census Mean (missing columns contained no data).
1	2	3	4	5	6	7	8	10	11	12	13	14	17	18	19	20	21	22	23	24	25	26	27	28
99	104	Diehl Susan	Head	F	W	71	Wd	7	6	PA	PA	PA	Eng	none					Y	N		O	F	H
		Straub Daniel	Boarder	M	W	67	S			PA	PA	PA	Eng	Laborer	Odd Jobs	W	N	40	N	N	Y