diff --git a/doc/source/whatsnew/v0.15.2.txt b/doc/source/whatsnew/v0.15.2.txt
index 377a9dea126e6..fc560782816ff 100644
--- a/doc/source/whatsnew/v0.15.2.txt
+++ b/doc/source/whatsnew/v0.15.2.txt
@@ -77,6 +77,7 @@ Enhancements
 
 Performance
 ~~~~~~~~~~~
+- Reduce memory usage when skiprows is an integer in read_csv (:issue:`8681`)
 
 .. _whatsnew_0152.experimental:
 
@@ -99,6 +100,7 @@ Bug Fixes
 - ``sql_schema`` now generates dialect appropriate ``CREATE TABLE`` statements (:issue:`8697`)
 - ``slice`` string method now takes step into account (:issue:`8754`)
 - Bug in ``BlockManager`` where setting values with different type would break block integrity (:issue:`8850`)
+- Bug in ``DatetimeIndex`` when using ``time`` object as key (:issue:`8667`)
 - Fix negative step support for label-based slices (:issue:`8753`)
 
   Old behavior:
@@ -144,7 +146,7 @@ Bug Fixes
 
 
 
-
+- BUG: Option context applies on __enter__ (:issue:`8514`)
 
 
 
@@ -153,8 +155,9 @@ Bug Fixes
 - Bug in `pd.infer_freq`/`DataFrame.inferred_freq` that prevented proper sub-daily frequency inference
   when the index contained DST days (:issue:`8772`).
 - Bug where index name was still used when plotting a series with ``use_index=False`` (:issue:`8558`).
-
 - Bugs when trying to stack multiple columns, when some (or all)
   of the level names are numbers (:issue:`8584`).
 - Bug in ``MultiIndex`` where ``__contains__`` returns wrong result if index is
   not lexically sorted or unique (:issue:`7724`)
+- BUG CSV: fix problem with trailing whitespace in skipped rows, (:issue:`8679`), (:issue:`8661`)
+- Regression in ``Timestamp`` does not parse 'Z' zone designator for UTC (:issue:`8771`)
diff --git a/pandas/core/common.py b/pandas/core/common.py
index 759f5f1dfaf7a..6aff67412d677 100644
--- a/pandas/core/common.py
+++ b/pandas/core/common.py
@@ -404,9 +404,13 @@ def array_equivalent(left, right, strict_nan=False):
 
     Examples
     --------
-    >>> array_equivalent(np.array([1, 2, nan]), np.array([1, 2, nan]))
+    >>> array_equivalent(
+    ...     np.array([1, 2, np.nan]),
+    ...     np.array([1, 2, np.nan]))
     True
-    >>> array_equivalent(np.array([1, nan, 2]), np.array([1, 2, nan]))
+    >>> array_equivalent(
+    ...     np.array([1, np.nan, 2]),
+    ...     np.array([1, 2, np.nan]))
     False
     """
 
@@ -2171,8 +2175,8 @@ def iterpairs(seq):
 
     Examples
     --------
-    >>> iterpairs([1, 2, 3, 4])
-    [(1, 2), (2, 3), (3, 4)
+    >>> list(iterpairs([1, 2, 3, 4]))
+    [(1, 2), (2, 3), (3, 4)]
     """
     # input may not be sliceable
     seq_it = iter(seq)
diff --git a/pandas/core/config.py b/pandas/core/config.py
index 60dc1d7d0341e..b59e07251ce3e 100644
--- a/pandas/core/config.py
+++ b/pandas/core/config.py
@@ -51,6 +51,7 @@
 import re
 
 from collections import namedtuple
+from contextlib import contextmanager
 import warnings
 from pandas.compat import map, lmap, u
 import pandas.compat as compat
@@ -384,19 +385,18 @@ def __init__(self, *args):
                 'option_context(pat, val, [(pat, val), ...)).'
             )
 
-        ops = list(zip(args[::2], args[1::2]))
+        self.ops = list(zip(args[::2], args[1::2]))
+
+    def __enter__(self):
         undo = []
-        for pat, val in ops:
+        for pat, val in self.ops:
             undo.append((pat, _get_option(pat, silent=True)))
 
         self.undo = undo
 
-        for pat, val in ops:
+        for pat, val in self.ops:
             _set_option(pat, val, silent=True)
 
-    def __enter__(self):
-        pass
-
     def __exit__(self, *args):
         if self.undo:
             for pat, val in self.undo:
@@ -681,8 +681,6 @@ def pp(name, ks):
 #
 # helpers
 
-from contextlib import contextmanager
-
 
 @contextmanager
 def config_prefix(prefix):
diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index 237012a71aeb4..a464b687209cb 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -3279,7 +3279,7 @@ def update(self, other, join='left', overwrite=True, filter_func=None,
         Parameters
         ----------
         other : DataFrame, or object coercible into a DataFrame
-        join : {'left', 'right', 'outer', 'inner'}, default 'left'
+        join : {'left'}, default 'left'
         overwrite : boolean, default True
             If True then overwrite values for common keys in the calling frame
         filter_func : callable(1d-array) -> 1d-array<boolean>, default None
diff --git a/pandas/core/generic.py b/pandas/core/generic.py
index 7201428e6b935..7b9ce2b86f730 100644
--- a/pandas/core/generic.py
+++ b/pandas/core/generic.py
@@ -2872,11 +2872,13 @@ def groupby(self, by=None, axis=0, level=None, as_index=True, sort=True,
         GroupBy object
 
         """
-
         from pandas.core.groupby import groupby
+
+        if level is None and by is None:
+            raise TypeError('You have to specify at least one of "by" and "level"')
         axis = self._get_axis_number(axis)
-        return groupby(self, by, axis=axis, level=level, as_index=as_index,
-                       sort=sort, group_keys=group_keys, squeeze=squeeze)
+        return groupby(self, by=by, axis=axis, level=level, as_index=as_index,
+                    sort=sort, group_keys=group_keys, squeeze=squeeze)
 
     def asfreq(self, freq, method=None, how=None, normalize=False):
         """
diff --git a/pandas/index.pyx b/pandas/index.pyx
index 73d886f10b241..9be7e7404f3fe 100644
--- a/pandas/index.pyx
+++ b/pandas/index.pyx
@@ -545,8 +545,14 @@ cdef class DatetimeEngine(Int64Engine):
                 val = _to_i8(val)
                 return self._get_loc_duplicates(val)
             values = self._get_index_values()
-            conv = _to_i8(val)
-            loc = values.searchsorted(conv, side='left')
+
+            try:
+                conv = _to_i8(val)
+                loc = values.searchsorted(conv, side='left')
+            except TypeError:
+                self._date_check_type(val)
+                raise KeyError(val)
+
             if loc == len(values) or util.get_value_at(values, loc) != conv:
                 raise KeyError(val)
             return loc
diff --git a/pandas/io/tests/test_parsers.py b/pandas/io/tests/test_parsers.py
index 228dad984bb3c..59647b4c781e5 100644
--- a/pandas/io/tests/test_parsers.py
+++ b/pandas/io/tests/test_parsers.py
@@ -3048,6 +3048,29 @@ def test_comment_skiprows(self):
         df = self.read_csv(StringIO(data), comment='#', skiprows=4)
         tm.assert_almost_equal(df.values, expected)
 
+    def test_trailing_spaces(self):
+        data = """skip
+random line with trailing spaces    
+skip
+1,2,3
+1,2.,4.
+random line with trailing tabs\t\t\t
+     
+5.,NaN,10.0
+"""
+        expected = pd.DataFrame([[1., 2., 4.],
+                    [5., np.nan, 10.]])
+        # this should ignore six lines including lines with trailing 
+        # whitespace and blank lines.  issues 8661, 8679
+        df = self.read_csv(StringIO(data.replace(',', '  ')), 
+                           header=None, delim_whitespace=True,
+                           skiprows=[0,1,2,3,5,6], skip_blank_lines=True)
+        tm.assert_frame_equal(df, expected)
+        df = self.read_table(StringIO(data.replace(',', '  ')), 
+                             header=None, delim_whitespace=True,
+                             skiprows=[0,1,2,3,5,6], skip_blank_lines=True)
+        tm.assert_frame_equal(df, expected)
+
     def test_comment_header(self):
         data = """# empty
 # second empty line
diff --git a/pandas/parser.pyx b/pandas/parser.pyx
index afaa5219ab0cd..0409ee56f22bb 100644
--- a/pandas/parser.pyx
+++ b/pandas/parser.pyx
@@ -86,6 +86,7 @@ cdef extern from "parser/tokenizer.h":
         EAT_COMMENT
         EAT_LINE_COMMENT
         WHITESPACE_LINE
+        SKIP_LINE
         FINISHED
 
     enum: ERROR_OVERFLOW
@@ -158,6 +159,7 @@ cdef extern from "parser/tokenizer.h":
         int header_end # header row end
 
         void *skipset
+        int64_t skip_first_N_rows
         int skip_footer
         double (*converter)(const char *, char **, char, char, char, int)
 
@@ -181,6 +183,8 @@ cdef extern from "parser/tokenizer.h":
     void parser_free(parser_t *self) nogil
     int parser_add_skiprow(parser_t *self, int64_t row)
 
+    int parser_set_skipfirstnrows(parser_t *self, int64_t nrows)
+
     void parser_set_default_options(parser_t *self)
 
     int parser_consume_rows(parser_t *self, size_t nrows)
@@ -524,10 +528,10 @@ cdef class TextReader:
 
     cdef _make_skiprow_set(self):
         if isinstance(self.skiprows, (int, np.integer)):
-            self.skiprows = range(self.skiprows)
-
-        for i in self.skiprows:
-            parser_add_skiprow(self.parser, i)
+            parser_set_skipfirstnrows(self.parser, self.skiprows)
+        else:
+            for i in self.skiprows:
+                parser_add_skiprow(self.parser, i)
 
     cdef _setup_parser_source(self, source):
         cdef:
diff --git a/pandas/src/datetime/np_datetime_strings.c b/pandas/src/datetime/np_datetime_strings.c
index 3f09de851e231..44363fd930510 100644
--- a/pandas/src/datetime/np_datetime_strings.c
+++ b/pandas/src/datetime/np_datetime_strings.c
@@ -363,7 +363,8 @@ convert_datetimestruct_local_to_utc(pandas_datetimestruct *out_dts_utc,
  *           to be cast to the 'unit' parameter.
  *
  * 'out' gets filled with the parsed date-time.
- * 'out_local' gets whether returned value contains timezone. 0 for UTC, 1 for local time.
+ * 'out_local' gets set to 1 if the parsed time contains timezone, 
+ *      to 0 otherwise.
  * 'out_tzoffset' gets set to timezone offset by minutes
  *      if the parsed time was in local time,
  *      to 0 otherwise. The values 'now' and 'today' don't get counted
@@ -785,11 +786,15 @@ parse_iso_8601_datetime(char *str, int len,
 
     /* UTC specifier */
     if (*substr == 'Z') {
-        /* "Z" means not local */
+        /* "Z" should be equivalent to tz offset "+00:00" */
         if (out_local != NULL) {
-            *out_local = 0;
+            *out_local = 1;
         }
 
+        if (out_tzoffset != NULL) {
+            *out_tzoffset = 0;
+         }
+
         if (sublen == 1) {
             goto finish;
         }
diff --git a/pandas/src/parser/tokenizer.c b/pandas/src/parser/tokenizer.c
index 9a7303b6874db..fc96cc5429775 100644
--- a/pandas/src/parser/tokenizer.c
+++ b/pandas/src/parser/tokenizer.c
@@ -156,6 +156,7 @@ void parser_set_default_options(parser_t *self) {
     self->thousands = '\0';
 
     self->skipset = NULL;
+    self-> skip_first_N_rows = -1;
     self->skip_footer = 0;
 }
 
@@ -444,21 +445,17 @@ static int end_line(parser_t *self) {
         }
     }
 
-    if (self->skipset != NULL) {
-        k = kh_get_int64((kh_int64_t*) self->skipset, self->file_lines);
-
-        if (k != ((kh_int64_t*)self->skipset)->n_buckets) {
-            TRACE(("Skipping row %d\n", self->file_lines));
-            // increment file line count
-            self->file_lines++;
-
-            // skip the tokens from this bad line
-            self->line_start[self->lines] += fields;
+    if (self->state == SKIP_LINE) {
+        TRACE(("Skipping row %d\n", self->file_lines));
+        // increment file line count
+        self->file_lines++;
+        
+        // skip the tokens from this bad line
+        self->line_start[self->lines] += fields;
 
-            // reset field count
-            self->line_fields[self->lines] = 0;
-            return 0;
-        }
+        // reset field count
+        self->line_fields[self->lines] = 0;
+        return 0;
     }
 
     /* printf("Line: %d, Fields: %d, Ex-fields: %d\n", self->lines, fields, ex_fields); */
@@ -556,6 +553,15 @@ int parser_add_skiprow(parser_t *self, int64_t row) {
     return 0;
 }
 
+int parser_set_skipfirstnrows(parser_t *self, int64_t nrows) {
+    // self->file_lines is zero based so subtract 1 from nrows
+    if (nrows > 0) {
+        self->skip_first_N_rows = nrows - 1;
+    }
+
+    return 0;
+}
+
 static int parser_buffer_bytes(parser_t *self, size_t nbytes) {
     int status;
     size_t bytes_read;
@@ -656,6 +662,15 @@ typedef int (*parser_op)(parser_t *self, size_t line_limit);
     TRACE(("datapos: %d, datalen: %d\n", self->datapos, self->datalen));
 
 
+int skip_this_line(parser_t *self, int64_t rownum) {
+    if (self->skipset != NULL) {
+        return ( kh_get_int64((kh_int64_t*) self->skipset, self->file_lines) != 
+                 ((kh_int64_t*)self->skipset)->n_buckets );
+    }
+    else {
+        return ( rownum <= self->skip_first_N_rows );
+    }
+}
 
 int tokenize_delimited(parser_t *self, size_t line_limit)
 {
@@ -688,10 +703,25 @@ int tokenize_delimited(parser_t *self, size_t line_limit)
 
         switch(self->state) {
 
+        case SKIP_LINE:
+//            TRACE(("tokenize_delimited SKIP_LINE %c, state %d\n", c, self->state));
+            if (c == '\n') {
+                END_LINE();
+            }
+            break;
+
         case START_RECORD:
             // start of record
-
-            if (c == '\n') {
+            if (skip_this_line(self, self->file_lines)) {
+                if (c == '\n') {
+                    END_LINE()
+                }
+                else {
+                    self->state = SKIP_LINE;
+                }
+                break;
+            }
+            else if (c == '\n') {
                 // \n\r possible?
                 if (self->skip_empty_lines)
                 {
@@ -1006,9 +1036,26 @@ int tokenize_delim_customterm(parser_t *self, size_t line_limit)
                self->state));
 
         switch(self->state) {
+
+        case SKIP_LINE:
+//            TRACE(("tokenize_delim_customterm SKIP_LINE %c, state %d\n", c, self->state));
+            if (c == self->lineterminator) {
+                END_LINE();
+            }
+            break;
+
         case START_RECORD:
             // start of record
-            if (c == self->lineterminator) {
+            if (skip_this_line(self, self->file_lines)) {
+                if (c == self->lineterminator) {
+                    END_LINE()
+                }
+                else {
+                    self->state = SKIP_LINE;
+                }
+                break;
+            }
+            else if (c == self->lineterminator) {
                 // \n\r possible?
                 if (self->skip_empty_lines)
                 {
@@ -1252,6 +1299,14 @@ int tokenize_whitespace(parser_t *self, size_t line_limit)
                self->state));
 
         switch(self->state) {
+
+        case SKIP_LINE:
+//            TRACE(("tokenize_whitespace SKIP_LINE %c, state %d\n", c, self->state));
+            if (c == '\n') {
+                END_LINE();
+            }
+            break;
+
         case WHITESPACE_LINE:
             if (c == '\n') {
                 self->file_lines++;
@@ -1283,9 +1338,17 @@ int tokenize_whitespace(parser_t *self, size_t line_limit)
 
         case START_RECORD:
             // start of record
-            if (c == '\n') {
-                // \n\r possible?
+            if (skip_this_line(self, self->file_lines)) {
+                if (c == '\n') {
+                    END_LINE()
+                }
+                else {
+                    self->state = SKIP_LINE;
+                }
+                break;
+            } else  if (c == '\n') {
                 if (self->skip_empty_lines)
+                // \n\r possible?
                 {
                     self->file_lines++;
                 }
diff --git a/pandas/src/parser/tokenizer.h b/pandas/src/parser/tokenizer.h
index 0947315fbe6b7..07f4153038dd8 100644
--- a/pandas/src/parser/tokenizer.h
+++ b/pandas/src/parser/tokenizer.h
@@ -127,6 +127,7 @@ typedef enum {
     EAT_COMMENT,
     EAT_LINE_COMMENT,
     WHITESPACE_LINE,
+    SKIP_LINE,
     FINISHED
 } ParserState;
 
@@ -203,6 +204,7 @@ typedef struct parser_t {
     int header_end;   // header row end
 
     void *skipset;
+    int64_t skip_first_N_rows;
     int skip_footer;
     double (*converter)(const char *, char **, char, char, char, int);
 
@@ -240,6 +242,8 @@ int parser_trim_buffers(parser_t *self);
 
 int parser_add_skiprow(parser_t *self, int64_t row);
 
+int parser_set_skipfirstnrows(parser_t *self, int64_t nrows);
+
 void parser_free(parser_t *self);
 
 void parser_set_default_options(parser_t *self);
diff --git a/pandas/tests/test_config.py b/pandas/tests/test_config.py
index dc5e9a67bdb65..3a8fdd877f5a0 100644
--- a/pandas/tests/test_config.py
+++ b/pandas/tests/test_config.py
@@ -425,3 +425,24 @@ def f3(key):
         options.c = 1
         self.assertEqual(len(holder), 1)
 
+    def test_option_context_scope(self):
+        # Ensure that creating a context does not affect the existing
+        # environment as it is supposed to be used with the `with` statement.
+        # See https://github.com/pydata/pandas/issues/8514
+
+        original_value = 60
+        context_value = 10
+        option_name = 'a'
+
+        self.cf.register_option(option_name, original_value)
+
+        # Ensure creating contexts didn't affect the current context.
+        ctx = self.cf.option_context(option_name, context_value)
+        self.assertEqual(self.cf.get_option(option_name), original_value)
+
+        # Ensure the correct value is available inside the context.
+        with ctx:
+            self.assertEqual(self.cf.get_option(option_name), context_value)
+
+        # Ensure the current context is reset
+        self.assertEqual(self.cf.get_option(option_name), original_value)
diff --git a/pandas/tests/test_groupby.py b/pandas/tests/test_groupby.py
index ef3fc03fc8d22..cd768423e492a 100644
--- a/pandas/tests/test_groupby.py
+++ b/pandas/tests/test_groupby.py
@@ -1961,6 +1961,9 @@ def test_groupby_level(self):
         # raise exception for non-MultiIndex
         self.assertRaises(ValueError, self.df.groupby, level=1)
 
+
+
+
     def test_groupby_level_index_names(self):
         ## GH4014 this used to raise ValueError since 'exp'>1 (in py2)
         df = DataFrame({'exp' : ['A']*3 + ['B']*3, 'var1' : lrange(6),}).set_index('exp')
@@ -1999,6 +2002,17 @@ def test_groupby_level_apply(self):
         result = frame['A'].groupby(level=0).count()
         self.assertEqual(result.index.name, 'first')
 
+    def test_groupby_args(self):
+        #PR8618 and issue 8015
+        frame = self.mframe
+        def j():
+             frame.groupby()
+        self.assertRaisesRegexp(TypeError, "You have to supply one of 'by' and 'level'", j)
+
+        def k():
+            frame.groupby(by=None, level=None)
+        self.assertRaisesRegexp(TypeError, "You have to supply one of 'by' and 'level'", k)
+
     def test_groupby_level_mapper(self):
         frame = self.mframe
         deleveled = frame.reset_index()
@@ -3689,8 +3703,9 @@ def test_cumcount(self):
         assert_series_equal(expected, sg.cumcount())
 
     def test_cumcount_empty(self):
-        ge = DataFrame().groupby()
-        se = Series().groupby()
+        dfe = DataFrame()
+        ge = dfe.groupby(dfe.index)
+        se = Series().groupby(by=1, level=2)
 
         e = Series(dtype='int64')  # edge case, as this is usually considered float
 
diff --git a/pandas/tests/test_index.py b/pandas/tests/test_index.py
index b7a18da3924c8..3c57dd764e3aa 100644
--- a/pandas/tests/test_index.py
+++ b/pandas/tests/test_index.py
@@ -1886,6 +1886,27 @@ def test_reindex_preserves_tz_if_target_is_empty_list_or_array(self):
         self.assertEqual(str(index.reindex([])[0].tz), 'US/Eastern')
         self.assertEqual(str(index.reindex(np.array([]))[0].tz), 'US/Eastern')
 
+    def test_time_loc(self):  # GH8667
+        from datetime import time
+        from pandas.index import _SIZE_CUTOFF
+
+        ns = _SIZE_CUTOFF + np.array([-100, 100],dtype=np.int64)
+        key = time(15, 11, 30)
+        start = key.hour * 3600 + key.minute * 60 + key.second
+        step = 24 * 3600
+
+        for n in ns:
+            idx = pd.date_range('2014-11-26', periods=n, freq='S')
+            ts = pd.Series(np.random.randn(n), index=idx)
+            i = np.arange(start, n, step)
+
+            tm.assert_array_equal(ts.index.get_loc(key), i)
+            tm.assert_series_equal(ts[key], ts.iloc[i])
+
+            left, right = ts.copy(), ts.copy()
+            left[key] *= -10
+            right.iloc[i] *= -10
+            tm.assert_series_equal(left, right)
 
 class TestPeriodIndex(Base, tm.TestCase):
     _holder = PeriodIndex
diff --git a/pandas/tseries/index.py b/pandas/tseries/index.py
index 202e30cc2eb5e..e7c001ac57c0a 100644
--- a/pandas/tseries/index.py
+++ b/pandas/tseries/index.py
@@ -1210,6 +1210,10 @@ def get_value(self, series, key):
 
             return self.get_value_maybe_box(series, key)
 
+        if isinstance(key, time):
+            locs = self.indexer_at_time(key)
+            return series.take(locs)
+
         try:
             return _maybe_box(self, Index.get_value(self, series, key), series, key)
         except KeyError:
@@ -1219,10 +1223,6 @@ def get_value(self, series, key):
             except (TypeError, ValueError, KeyError):
                 pass
 
-            if isinstance(key, time):
-                locs = self.indexer_at_time(key)
-                return series.take(locs)
-
             try:
                 return self.get_value_maybe_box(series, key)
             except (TypeError, ValueError, KeyError):
@@ -1250,6 +1250,9 @@ def get_loc(self, key):
             stamp = Timestamp(key, tz=self.tz)
             return self._engine.get_loc(stamp)
 
+        if isinstance(key, time):
+            return self.indexer_at_time(key)
+
         try:
             return Index.get_loc(self, key)
         except (KeyError, ValueError):
@@ -1258,9 +1261,6 @@ def get_loc(self, key):
             except (TypeError, KeyError, ValueError):
                 pass
 
-            if isinstance(key, time):
-                return self.indexer_at_time(key)
-
             try:
                 stamp = Timestamp(key, tz=self.tz)
                 return self._engine.get_loc(stamp)
diff --git a/pandas/tseries/tests/test_tslib.py b/pandas/tseries/tests/test_tslib.py
index 9adcbb4ea4a41..6c358bd99e620 100644
--- a/pandas/tseries/tests/test_tslib.py
+++ b/pandas/tseries/tests/test_tslib.py
@@ -6,7 +6,7 @@
 import datetime
 
 from pandas.core.api import Timestamp, Series
-from pandas.tslib import period_asfreq, period_ordinal
+from pandas.tslib import period_asfreq, period_ordinal, get_timezone
 from pandas.tseries.index import date_range
 from pandas.tseries.frequencies import get_freq
 import pandas.tseries.offsets as offsets
@@ -298,6 +298,9 @@ def test_barely_oob_dts(self):
         # One us more than the maximum is an error
         self.assertRaises(ValueError, Timestamp, max_ts_us + one_us)
 
+    def test_utc_z_designator(self):
+        self.assertEqual(get_timezone(Timestamp('2014-11-02 01:00Z').tzinfo), 'UTC')
+
 
 class TestDatetimeParsingWrappers(tm.TestCase):
     def test_does_not_convert_mixed_integer(self):
diff --git a/pandas/tseries/tools.py b/pandas/tseries/tools.py
index 45bea00ac104f..f29ab14ed8745 100644
--- a/pandas/tseries/tools.py
+++ b/pandas/tseries/tools.py
@@ -177,7 +177,7 @@ def to_datetime(arg, errors='ignore', dayfirst=False, utc=None, box=True,
                 format=None, coerce=False, unit='ns',
                 infer_datetime_format=False):
     """
-    Convert argument to datetime
+    Convert argument to datetime.
 
     Parameters
     ----------
@@ -198,13 +198,16 @@ def to_datetime(arg, errors='ignore', dayfirst=False, utc=None, box=True,
     coerce : force errors to NaT (False by default)
     unit : unit of the arg (D,s,ms,us,ns) denote the unit in epoch
         (e.g. a unix timestamp), which is an integer/float number
-    infer_datetime_format: boolean, default False
+    infer_datetime_format : boolean, default False
         If no `format` is given, try to infer the format based on the first
         datetime string. Provides a large speed-up in many cases.
 
     Returns
     -------
-    ret : datetime if parsing succeeded
+    ret : datetime if parsing succeeded. Return type depends on input:
+        - list-like: DatetimeIndex
+        - Series: Series of datetime64 dtype
+        - scalar: Timestamp
 
     Examples
     --------
diff --git a/vb_suite/io_bench.py b/vb_suite/io_bench.py
index 0b9f68f0e6ed5..a70c543ca59eb 100644
--- a/vb_suite/io_bench.py
+++ b/vb_suite/io_bench.py
@@ -21,6 +21,22 @@
 read_csv_standard = Benchmark("read_csv('__test__.csv')", setup1,
                               start_date=datetime(2011, 9, 15))
 
+#----------------------------------
+# skiprows
+
+setup1 = common_setup + """
+index = tm.makeStringIndex(20000)
+df = DataFrame({'float1' : randn(20000),
+                'float2' : randn(20000),
+                'string1' : ['foo'] * 20000,
+                'bool1' : [True] * 20000,
+                'int1' : np.random.randint(0, 200000, size=20000)},
+               index=index)
+df.to_csv('__test__.csv')
+"""
+
+read_csv_skiprows = Benchmark("read_csv('__test__.csv', skiprows=10000)", setup1,
+                              start_date=datetime(2011, 9, 15))
 
 #----------------------------------------------------------------------
 # write_csv