diff -uwr nethack-3.4.3/src/worm.c nethack-long-worm-fix-C343-324/src/worm.c
--- nethack-3.4.3/src/worm.c	2003-12-08 00:39:13.000000000 +0100
+++ nethack-long-worm-fix-C343-324/src/worm.c	2008-10-26 15:24:55.000000000 +0100
@@ -303,6 +303,23 @@
 	    (void) mattacku(worm);
 }
 
+/*  cutoff()
+ *
+ *  Remove the tail of a worm and adjust the hp of the worm.
+ */
+void
+cutoff(worm, tail)
+    struct monst *worm;
+    struct wseg *tail;
+{
+	if (flags.mon_moving)
+	    pline("Part of the tail of %s is cut off.", mon_nam(worm));
+	else
+	    You("cut part of the tail off of %s.", mon_nam(worm));
+	toss_wsegs(tail, TRUE);
+	if (worm->mhp > 1) worm->mhp /= 2;
+}
+
 /*  cutworm()
  *
  *  Check for mon->wormno before calling this function!
@@ -368,17 +385,15 @@
 
     /* Sometimes the tail end dies. */
     if (rn2(3) || !(new_wnum = get_wormno())) {
-	if (flags.mon_moving)
-	    pline("Part of the tail of %s is cut off.", mon_nam(worm));
-	else
-	    You("cut part of the tail off of %s.", mon_nam(worm));
-	toss_wsegs(new_tail, TRUE);
-	if (worm->mhp > 1) worm->mhp /= 2;
+	cutoff(worm, new_tail);
 	return;
     }
 
     remove_monster(x, y);		/* clone_mon puts new head here */
-    new_worm = clone_mon(worm, x, y);
+    if (!(new_worm = clone_mon(worm, x, y))) {
+	cutoff(worm, new_tail);
+	return;
+    }
     new_worm->wormno = new_wnum;	/* affix new worm number */
 
     /* Devalue the monster level of both halves of the worm. */