The Chevy’s price has an asterisk, “price after tax credit”. If the Prius qualifies for the same credit, it isn’t mention on the page you linked to. I may also be thinking of the cost of the Volt I, which I believe cost more than 40K before tax credit. If this new one is less expensive (and a more conventional hybrid), my apologies.
Federal Tax Credit Plug-in hybrid-electric vehicles
http://fueleconomy.gov/feg/taxphevb.shtml
http://fueleconomy.gov/feg/phevtech.shtml
The tax credit for series versus parallel hybrids are different. With the 2016 models, the credits will be the same category.