1b. Genital pores located laterally .............................................................................................................................. [3]

2a Rostellum with bothria or "sucking groves" as holdfast structures ................................. Order Pseudophyllidea

2a.  Dibothriocephalus latus [Scolex]  [Proglottids]

2b. Rostellum with suckers and uterus with paruterine organ ..............................................Family Mesocestoididae

2b. Mesocestoides   [Scolex]  [Scolex]  [Scolex] [Proglottids]  [Proglottids]

3a. Gravid proglottids longer than wide .....................................................................................................................[4]

3b. Mature and gravid proglottids wider than long .................................................................................................. [5]

4a. Scolex broad and armed with circles of hooks .............................................................................Family Taeniidae

4a. Taenia [Scolex] [Proglottids] and Echinococcus [Adult worm]

4b. Scolex tiny with retractable, armed rostellum ...........................................................................Family Dilepididae

4b. Dipylidium caninum [Scolex] [Proglottids]

5a. Rostellum tiny, armed  and retractable ..............................................................................Family Hymenolepidae

5a. Hymenolepus [Scolex] [proglottids]

5b. Rostellum large and unarmed ..............................................................................................................................[6]

6a. Proglottids fringed on posterior margin ...........................................................................Family Thysanosomidae

6a. Thysanosoma actinoides [Scolex] [Proglottids]