diff --git a/tardis/analysis.py b/tardis/analysis.py
index 32653b6429c..98911129cf3 100644
--- a/tardis/analysis.py
+++ b/tardis/analysis.py
@@ -89,25 +89,29 @@ def update_last_interaction_filter(self):
         self.last_line_out = self.lines.iloc[self.last_line_interaction_out_id[packet_filter]]
 
         if self.atomic_number is not None:
-            self.last_line_in = self.last_line_in[self.last_line_in.atomic_number == self.atomic_number]
-            self.last_line_out = self.last_line_out[self.last_line_out.atomic_number == self.atomic_number]
+            self.last_line_in = self.last_line_in.xs(self.atomic_number, level='atomic_number', drop_level=False)
+            self.last_line_out = self.last_line_out.xs(self.atomic_number, level='atomic_number', drop_level=False)
 
         if self.ion_number is not None:
-            self.last_line_in = self.last_line_in[self.last_line_in.ion_number == self.ion_number]
-            self.last_line_out = self.last_line_out[self.last_line_out.ion_number == self.ion_number]
+            self.last_line_in = self.last_line_in.xs(self.ion_number, level='ion_number', drop_level=False)
+            self.last_line_out = self.last_line_out.xs(self.ion_number, level='ion_number', drop_level=False)
 
 
-        last_line_in_count = self.last_line_in.wavelength.groupby(level=0).count()
-        last_line_out_count = self.last_line_out.wavelength.groupby(level=0).count()
+        last_line_in_count = self.last_line_in.line_id.value_counts()
+        last_line_out_count = self.last_line_out.line_id.value_counts()
 
-        self.last_line_in_table = self.lines[['wavelength', 'atomic_number', 'ion_number', 'level_number_lower',
-                                              'level_number_upper']].ix[last_line_in_count.index]
+        self.last_line_in_table = self.last_line_in.reset_index()[
+                [
+                    'wavelength', 'atomic_number', 'ion_number',
+                    'level_number_lower', 'level_number_upper']]
         self.last_line_in_table['count'] = last_line_in_count
-        self.last_line_in_table.sort('count', ascending=False, inplace=True)
-        self.last_line_out_table = self.lines[['wavelength', 'atomic_number', 'ion_number', 'level_number_lower',
-                                              'level_number_upper']].ix[last_line_out_count.index]
+        self.last_line_in_table.sort_values(by='count', ascending=False, inplace=True)
+        self.last_line_out_table = self.last_line_out.reset_index()[
+                [
+                    'wavelength', 'atomic_number', 'ion_number',
+                    'level_number_lower', 'level_number_upper']]
         self.last_line_out_table['count'] = last_line_out_count
-        self.last_line_out_table.sort('count', ascending=False, inplace=True)
+        self.last_line_out_table.sort_values(by='count', ascending=False, inplace=True)
 
 
     def update_last_interaction_line_in_nu_filter(self):
diff --git a/tardis/gui/widgets.py b/tardis/gui/widgets.py
index 5adbed691cc..fe13b70a122 100644
--- a/tardis/gui/widgets.py
+++ b/tardis/gui/widgets.py
@@ -959,7 +959,7 @@ def __init__(self, line_interaction_analysis, atom_data, lines_data, description
         self.layout = QtGui.QHBoxLayout()
         self.line_interaction_analysis = line_interaction_analysis
         self.atom_data = atom_data
-        self.lines_data = lines_data
+        self.lines_data = lines_data.reset_index().set_index('line_id')
         line_interaction_species_group = \
         line_interaction_analysis.last_line_in.groupby(['atomic_number', 
             'ion_number'])
@@ -990,31 +990,34 @@ def on_species_clicked(self, index):
         last_line_in = self.line_interaction_analysis.last_line_in
         last_line_out = self.line_interaction_analysis.last_line_out
 
-        last_line_in_filter = (last_line_in.atomic_number == current_species[0]).values & \
-                              (last_line_in.ion_number == current_species[1]).values
+        current_last_line_in = last_line_in.xs(
+                key=(current_species[0], current_species[1]),
+                level=['atomic_number', 'ion_number'],
+                drop_level=False).reset_index()
+        current_last_line_out = last_line_out.xs(
+                key=(current_species[0], current_species[1]),
+                level=['atomic_number', 'ion_number'],
+                drop_level=False).reset_index()
 
-        current_last_line_in = last_line_in[last_line_in_filter].reset_index()
-        current_last_line_out = last_line_out[last_line_in_filter].reset_index()
-
-        current_last_line_in['line_id_out'] = current_last_line_out['line_id']
+        current_last_line_in['line_id_out'] = current_last_line_out.line_id
 
 
         last_line_in_string = []
         last_line_count = []
-        grouped_line_interactions = current_last_line_in.groupby(['line_id', 
-            'line_id_out'])
+        grouped_line_interactions = current_last_line_in.groupby(
+                ['line_id', 'line_id_out'])
         exc_deexc_string = 'exc. %d-%d (%.2f A) de-exc. %d-%d (%.2f A)'
 
         for line_id, row in grouped_line_interactions.wavelength.count().iteritems():
-            current_line_in = self.lines_data.ix[line_id[0]]
-            current_line_out = self.lines_data.ix[line_id[1]]
+            current_line_in = self.lines_data.loc[line_id[0]]
+            current_line_out = self.lines_data.loc[line_id[1]]
             last_line_in_string.append(exc_deexc_string % (
                 current_line_in['level_number_lower'],
-               current_line_in['level_number_upper'],
-               current_line_in['wavelength'],
-               current_line_out['level_number_upper'],
-               current_line_out['level_number_lower'],
-               current_line_out['wavelength']))
+                current_line_in['level_number_upper'],
+                current_line_in['wavelength'],
+                current_line_out['level_number_upper'],
+                current_line_out['level_number_lower'],
+                current_line_out['wavelength']))
             last_line_count.append(int(row))