This is because the game considers the spell resolving, not allowing you to respond, as players cannot activate abilities, put triggers on the stack, or cast spells while a spell is resolving
As it turns out, Richard Thomas, the artist tasked with the card's artwork, knew very well what hyalopterous meant, but thought that a lemure was the same as the large-eyed, ring-tailed Madagascarian primate, the lemur
1 - Sylvan Tutor Green decks already have powerful tutors with Chord of Calling, Archdruid's Charm and even Natural Order to cheat on mana costs, and now, Sylvan Tutor joins this wide range to search for any creature for just one mana
Vaevictis Asmadi, the Dire can definitely be a great Jund commander for a chaos deck