USB shield – usb host shield
if you will not use External Power please be sure this jumpers are soldered as below :

so after soldering it will be like this image

Prototype Shield for Arduino MEGA
1 × 35 SAR
Medium Kit for Arduino Projects
1 × 229 SAR Subtotal: 264 SAR
Prototype Shield for Arduino MEGA
1 × 35 SAR
Medium Kit for Arduino Projects
1 × 229 SAR Subtotal: 264 SAR
if you will not use External Power please be sure this jumpers are soldered as below :

so after soldering it will be like this image

All Electronics Components
All Electronics Components
All Electronics Components
All Electronics Components
All Electronics Components
All Electronics Components
All Electronics Components
All Electronics Components