Which constellation represents a smaller dog following Orion?

The constellation representing a smaller dog following Orion is Canis Minor. This constellation, which translates to "Lesser Dog," is positioned near Orion in the night sky and is often depicted as a small dog following the hunter of the constellation Orion. Canis Minor is most notable for containing the bright star Procyon, which is one of the brightest stars in the night sky and part of the Winter Triangle alongside Sirius from Canis Major and Betelgeuse from Orion.

In contrast, Canis Major, which translates to "Greater Dog," is another constellation associated with Orion but represents the larger dog, Sirius being its most prominent star. Aquila is a constellation that represents an eagle, and Virgo represents a maiden, neither of which are related to the imagery of dogs or the hunter's companions in the sky. Thus, Canis Minor clearly identifies the smaller dog following Orion, making it the correct answer.