diff --git a/pxr/imaging/hd/unitTestNullRenderDelegate.cpp b/pxr/imaging/hd/unitTestNullRenderDelegate.cpp
index e1a5325e2c..1d22c2a91e 100644
--- a/pxr/imaging/hd/unitTestNullRenderDelegate.cpp
+++ b/pxr/imaging/hd/unitTestNullRenderDelegate.cpp
@@ -25,6 +25,7 @@
 #include "pxr/imaging/hd/bufferArray.h"
 #include "pxr/imaging/hd/camera.h"
 #include "pxr/imaging/hd/coordSys.h"
+#include "pxr/imaging/hd/light.h"
 #include "pxr/imaging/hd/material.h"
 #include "pxr/imaging/hd/mesh.h"
 #include "pxr/imaging/hd/basisCurves.h"
@@ -235,6 +236,29 @@ class Hd_NullMaterial final : public HdMaterial {
     Hd_NullMaterial &operator =(const Hd_NullMaterial &) = delete;
 };
 
+class Hd_NullLight final : public HdLight {
+public:
+    Hd_NullLight(SdfPath const& id) : HdLight(id) {}
+    virtual ~Hd_NullLight() = default;
+
+    virtual void Sync(HdSceneDelegate *sceneDelegate,
+                      HdRenderParam   *renderParam,
+                      HdDirtyBits     *dirtyBits) override
+    {
+        *dirtyBits = HdLight::Clean;
+    }
+
+    virtual HdDirtyBits GetInitialDirtyBitsMask() const override
+    {
+        return HdLight::AllDirty;
+    }
+
+private:
+    Hd_NullLight()                                 = delete;
+    Hd_NullLight(const Hd_NullLight &)             = delete;
+    Hd_NullLight &operator =(const Hd_NullLight &) = delete;
+};
+
 class Hd_NullCoordSys final : public HdCoordSys {
 public:
     Hd_NullCoordSys(SdfPath const& id) : HdCoordSys(id) {}
@@ -290,6 +314,7 @@ const TfTokenVector Hd_UnitTestNullRenderDelegate::SUPPORTED_SPRIM_TYPES =
 {
     HdPrimTypeTokens->camera,
     HdPrimTypeTokens->coordSys,
+    HdPrimTypeTokens->domeLight,
     HdPrimTypeTokens->material
 };
 
@@ -369,6 +394,8 @@ Hd_UnitTestNullRenderDelegate::CreateSprim(TfToken const& typeId,
 {
     if (typeId == HdPrimTypeTokens->material) {
         return new Hd_NullMaterial(sprimId);
+    } else if (typeId == HdPrimTypeTokens->domeLight) {
+        return new Hd_NullLight(SdfPath::EmptyPath());
     } else if (typeId == HdPrimTypeTokens->coordSys) {
         return new Hd_NullCoordSys(sprimId);
     } else if (typeId == HdPrimTypeTokens->camera) {
@@ -384,6 +411,8 @@ Hd_UnitTestNullRenderDelegate::CreateFallbackSprim(TfToken const& typeId)
 {
     if (typeId == HdPrimTypeTokens->material) {
         return new Hd_NullMaterial(SdfPath::EmptyPath());
+    } else if (typeId == HdPrimTypeTokens->domeLight) {
+        return new Hd_NullLight(SdfPath::EmptyPath());
     } else if (typeId == HdPrimTypeTokens->coordSys) {
         return new Hd_NullCoordSys(SdfPath::EmptyPath());
     } else if (typeId == HdPrimTypeTokens->camera) {
diff --git a/pxr/usdImaging/usdImaging/instanceAdapter.cpp b/pxr/usdImaging/usdImaging/instanceAdapter.cpp
index 2b30d1d8d5..51b47ceb05 100644
--- a/pxr/usdImaging/usdImaging/instanceAdapter.cpp
+++ b/pxr/usdImaging/usdImaging/instanceAdapter.cpp
@@ -1541,21 +1541,60 @@ UsdImagingInstanceAdapter::MarkVisibilityDirty(UsdPrim const& prim,
     }
 }
 
+struct UsdImagingInstanceAdapter::_GetInstanceCategoriesFn
+{
+    _GetInstanceCategoriesFn(
+        const UsdImagingInstanceAdapter* adapter,
+        const UsdImaging_CollectionCache* cc, 
+        std::vector<VtTokenArray>* result) : 
+        _adapter(adapter),
+        _cc(cc),
+        _result(result)
+    { }
+
+    void Initialize(size_t numInstances)
+    { 
+        _result->resize(numInstances);
+    }
+
+    bool operator()(const std::vector<UsdPrim>& ctx, size_t idx)
+    {
+        // We must query the collections cache using the instance's stage path, 
+        // not its proxy path. _GetStagePath() reconstructs the stage path
+        // from the instancing context.)
+        const SdfPath& path = _GetStagePath(ctx);
+        if (path.IsEmpty()) {
+            return false;
+        }
+        _result->at(idx) = _cc->ComputeCollectionsContainingPath(path);
+        return true;
+    }
+
+    SdfPath _GetStagePath(const std::vector<UsdPrim>& ctx)
+    {
+        SdfPathVector chain;
+        chain.reserve(ctx.size());
+        for (const UsdPrim& prim : ctx) {
+            chain.push_back(prim.GetPath());
+        }
+        return _adapter->_GetPrimPathFromInstancerChain(chain);
+    }
+
+    const UsdImagingInstanceAdapter* _adapter;
+    const UsdImaging_CollectionCache* _cc;
+    std::vector<VtTokenArray>* _result;
+};
+
 /*virtual*/
 std::vector<VtArray<TfToken>>
 UsdImagingInstanceAdapter::GetInstanceCategories(UsdPrim const& prim) 
 {
     HD_TRACE_FUNCTION();
-    std::vector<VtArray<TfToken>> categories;
-    if (const _InstancerData* instancerData = 
-        TfMapLookupPtr(_instancerData, prim.GetPath())) {
-        UsdImaging_CollectionCache& cc = _GetCollectionCache();
-        categories.reserve(instancerData->instancePaths.size());
-        for (SdfPath const& p: instancerData->instancePaths) {
-            categories.push_back(cc.ComputeCollectionsContainingPath(p));
-        }
-    }
-    return categories;
+    const UsdImaging_CollectionCache& cc = _GetCollectionCache();
+    std::vector<VtTokenArray> result;
+    _GetInstanceCategoriesFn catsFn(this, &cc, &result);
+    _RunForAllInstancesToDraw(prim, &catsFn);
+    return result;
 }
 
 /*virtual*/
diff --git a/pxr/usdImaging/usdImaging/instanceAdapter.h b/pxr/usdImaging/usdImaging/instanceAdapter.h
index 153f1c6b14..6fb5de4e94 100644
--- a/pxr/usdImaging/usdImaging/instanceAdapter.h
+++ b/pxr/usdImaging/usdImaging/instanceAdapter.h
@@ -460,6 +460,7 @@ class UsdImagingInstanceAdapter : public UsdImagingPrimAdapter
 
     struct _PopulateInstanceSelectionFn;
     struct _GetScenePrimPathsFn;
+    struct _GetInstanceCategoriesFn;
 
     // Helper functions for dealing with "actual" instances to be drawn.
     //