Spiders, ticks, and horseshoe crabs belong to the subphylum Mandibulata.
Dragonflies are more closely related to scorpionflies than to stoneflies.
The immature stages of some holometabolous insects are called naiads. Orthoptera and Hymenoptera have chewing mouthparts. Both Arthropods and Onychophorans have open circulatory systems. A. Hymenoptera C. Orthoptera B. Plecoptera D. Thysanura 7. A. Crustacea C. Arachnida B. Myriapoda D. Xiphosura 8.