diff --git a/third_party/2/requests/adapters.pyi b/third_party/2/requests/adapters.pyi
index 109dc9a3e..00cc000dc 100644
--- a/third_party/2/requests/adapters.pyi
+++ b/third_party/2/requests/adapters.pyi
@@ -1,6 +1,6 @@
 # Stubs for requests.adapters (Python 3)
 
-from typing import Any
+from typing import Any, Container, Union, Tuple
 from . import models
 from .packages.urllib3 import poolmanager
 from .packages.urllib3 import response
@@ -13,6 +13,7 @@ from . import cookies
 from . import exceptions
 from . import auth
 
+PreparedRequest = models.PreparedRequest
 Response = models.Response
 PoolManager = poolmanager.PoolManager
 proxy_from_url = poolmanager.proxy_from_url
@@ -43,9 +44,11 @@ DEFAULT_RETRIES = ...  # type: Any
 
 class BaseAdapter:
     def __init__(self) -> None: ...
-    # TODO: "request" parameter not actually supported, added to please mypy.
-    def send(self, request=...): ...
-    def close(self): ...
+    def send(self, request: PreparedRequest, stream=False,
+             timeout: Union[None, float, Tuple[float, float]]=None,
+             verify=False,
+             cert: Union[None, Union[str, unicode, bytes], Container[Union[str, unicode]]]=None) -> Response: ...
+    def close(self) -> None: ...
 
 class HTTPAdapter(BaseAdapter):
     __attrs__ = ...  # type: Any
diff --git a/third_party/2/requests/sessions.pyi b/third_party/2/requests/sessions.pyi
index 35ea3f748..9387f7726 100644
--- a/third_party/2/requests/sessions.pyi
+++ b/third_party/2/requests/sessions.pyi
@@ -1,6 +1,7 @@
 # Stubs for requests.sessions (Python 2.7)
 
 from typing import Any, Union, MutableMapping, Text, Optional, IO, Tuple, Callable
+from . import adapters
 from . import auth
 from . import compat
 from . import cookies
@@ -14,6 +15,7 @@ from . import structures
 from . import adapters
 from . import status_codes
 
+BaseAdapter = adapters.BaseAdapter
 OrderedDict = compat.OrderedDict
 cookiejar_from_dict = cookies.cookiejar_from_dict
 extract_cookies_to_jar = cookies.extract_cookies_to_jar
@@ -99,6 +101,6 @@ class Session(SessionRedirectMixin):
     def merge_environment_settings(self, url, proxies, stream, verify, cert): ...
     def get_adapter(self, url): ...
     def close(self) -> None: ...
-    def mount(self, prefix, adapter): ...
+    def mount(self, prefix: str, adapter: BaseAdapter) -> None: ...
 
 def session() -> Session: ...
diff --git a/third_party/3/requests/adapters.pyi b/third_party/3/requests/adapters.pyi
index 109dc9a3e..d896f1a9e 100644
--- a/third_party/3/requests/adapters.pyi
+++ b/third_party/3/requests/adapters.pyi
@@ -1,6 +1,6 @@
 # Stubs for requests.adapters (Python 3)
 
-from typing import Any
+from typing import Any, Container, Union, Tuple
 from . import models
 from .packages.urllib3 import poolmanager
 from .packages.urllib3 import response
@@ -13,6 +13,7 @@ from . import cookies
 from . import exceptions
 from . import auth
 
+PreparedRequest = models.PreparedRequest
 Response = models.Response
 PoolManager = poolmanager.PoolManager
 proxy_from_url = poolmanager.proxy_from_url
@@ -43,10 +44,12 @@ DEFAULT_RETRIES = ...  # type: Any
 
 class BaseAdapter:
     def __init__(self) -> None: ...
-    # TODO: "request" parameter not actually supported, added to please mypy.
-    def send(self, request=...): ...
-    def close(self): ...
-
+    def send(self, request: PreparedRequest, stream=False,
+             timeout: Union[None, float, Tuple[float, float]]=None,
+             verify=False,
+             cert: Union[None, Union[str, bytes], Container[Union[str, bytes]]]=None
+             ) -> Response: ...
+    def close(self) -> None: ...
 class HTTPAdapter(BaseAdapter):
     __attrs__ = ...  # type: Any
     max_retries = ...  # type: Any
diff --git a/third_party/3/requests/sessions.pyi b/third_party/3/requests/sessions.pyi
index 9bc3a0efd..d81191cee 100644
--- a/third_party/3/requests/sessions.pyi
+++ b/third_party/3/requests/sessions.pyi
@@ -1,6 +1,7 @@
 # Stubs for requests.sessions (Python 3)
 
 from typing import Any, Union, MutableMapping, Text, Optional, IO, Tuple, Callable
+from . import adapters
 from . import auth
 from . import compat
 from . import cookies
@@ -14,6 +15,7 @@ from . import structures
 from . import adapters
 from . import status_codes
 
+BaseAdapter = adapters.BaseAdapter
 OrderedDict = compat.OrderedDict
 cookiejar_from_dict = cookies.cookiejar_from_dict
 extract_cookies_to_jar = cookies.extract_cookies_to_jar
@@ -99,6 +101,8 @@ class Session(SessionRedirectMixin):
     def merge_environment_settings(self, url, proxies, stream, verify, cert): ...
     def get_adapter(self, url): ...
     def close(self) -> None: ...
-    def mount(self, prefix, adapter): ...
+    def mount(self, prefix:
+              Union[str, bytes],
+              adapter: BaseAdapter) -> None: ...
 
 def session() -> Session: ...