Did Judas Iscariot participate in the First Holy Eucharist? At John 13:1-30 we see the narrative of the last Passover meal that Jesus partook with his disciples, in which  Judas is identified as the one who would betray him :


  .... After saying this Jesus was troubled in spirit, and declared, “Very truly, I tell you, one of you will betray me.” ....  So while reclining next to Jesus, he (John )  asked him, “Lord, who is it?” .  Jesus answered, “It is the one to whom I give this piece of bread when I have dipped it in the dish.” So when he had dipped the piece of bread, he gave it to Judas son of Simon Iscariot. After he received the piece of bread, Satan entered into him. Jesus said to him, “Do quickly what you are going to do.” ... So, after receiving the piece of bread, he immediately went out. And it was night


Now, the Gospel according John does not contain an explcit narration of the Institution of Holy Eucharist . Reading that with I Corinthians 11:25 which says  that the supper had been ended as Jesus took the cup calling it  the new covenant of His Blood, one is inclined to believe that Judas had left the venue even before the Eucharist was constituted. 

My question therefore, is: Does the Catholic Church categorically teach that Judas Iscariot  participated in the First Eucharist instituted by Jesus at the Last Supper ? If it does not, why do the images of Last Supper that we have,  contain the picture of twelve Apostles ?
Did Judas Iscariot participate in the First Holy Eucharist?

The short answer seems to be yes.

Does the Catholic Church categorically teach that Judas Iscariot participated in the First Eucharist instituted by Jesus at the Last Supper?

The short answer is that there is room to doubt, but the Church tends to think that Judas Iscariot was present, St. Thomas Aquinas and St. John Chrysostom both say yes to this question.

Dr. Taylor Marshall explain it this way:


  Did Our Lord give the Holy Eucharist to Judas Iscariot at the Last Supper and First Mass? Saint John Chrysostom explains the Apostolic Tradition that Christ did indeed give the Holy Eucharist to Judas Iscariot:
  
  
    Judas was not converted while partaking of the sacred mysteries. Hence on both sides his crime becomes the more heinous, both because imbued with such a purpose he approached the mysteries, and because he became none the better for approaching, neither from fear, nor from the benefit received, nor from the honor conferred on him.” – Saint John Chrysostom, Homily 82 on Matthew
  
  
  Saint Dionysius* says (Eccl. Hier. iii) and Saint Augustine (Tract. lxii in Joan.) also confirm that Judas received the Holy Eucharist.
  
  What is the theological significance? Saint Thomas Aquinas explains:
  
  
    And this would have been quite proper [to refuse Judas the Eucharist], if the malice of Judas be considered. But since Christ was to serve us as a pattern of justice, it was not in keeping with His teaching authority to sever Judas, a hidden sinner, from Communion with the others without an accuser and evident proof. lest the Church’s prelates might have an example for doing the like, and lest Judas himself being exasperated might take occasion of sinning. 
    This reveals that secret sinners continue to receive the Holy Eucharist. But this begs the question. What about public sinners? The Chruch Fathers and Saint Thomas Aquinas say that public sinners should not be allowed to receive the Holy Eucharist. For Saint Augustine’s take, see Summa theologiae III q. 80, a. 6.
  
  
  Did Judas Iscariot Receive the Holy Eucharist?