Immature parasites (4)
I believe the answer is:
nits
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">immature parasites</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for nits that I've seen before include "Tins of parasitic insect eggs" , "Head louse eggs" , "Head lice" , "Fools" , "Eggs of lice" .)