digraph "tree" {
// The problem disappeared when I removed the "ELEM3 -> ID5;" line!
//size="4,5";
ordering=out;
node [shape=plaintext];
SPEC -> DEF2;
SPEC -> DEF1;
DEF1 -> ID1;
DEF1 -> SET1;
DEF1 -> SC1;
DEF2 -> ID2;
DEF2 -> SET2;
DEF2 -> SC2;
SET1 -> OPEN1;
SET1 -> ELEM1;
SET1 -> SC3;
SET1 -> ELEM2;
SET1 -> CLOSE1;
ELEM1 -> ID3;
SET2 -> OPEN2;
SET2 -> ELEM3;
SET2 -> CLOSE2;
ELEM2 -> ID4;
ELEM3 -> ID5;
DEF1 [label=DEF];
DEF2 [label=DEF];
SET1 [label=SET];
SC1 [label=";"];
SC3 [label=";"];
SET2 [label=SET];
SC2 [label=";"];
OPEN1 [label="{"];
OPEN2 [label="{"];
CLOSE1 [label="}"];
CLOSE2 [label="}"];
ELEM1 [label=ELEMENT];
ELEM2 [label=ELEMENT];
ELEM3 [label=ELEMENT];
ID1 [label=cities];
ID2 [label=insects];
ID3 [label=andover];
ID4 [label=boston];
ID5 [label=fly];
}