P-61 Black Widow with missile

I share with you some pictures showing a flying P-61 with a missile under the fuselage. Does anyone know what kind of missile is this and was used operationally? The link also contains photographs of the plane now testing some kind of jet engine. Photos can be viewed by visiting the link below:


http://aviacaoemfloripa.blogspot.com...especiais.html


Best Regards.