What is one key difference between Arachnids and true insects?

One key difference between arachnids and true insects is that arachnids possess a cephalothorax, which is a fused region that combines the head and thorax. In contrast, true insects have a distinct head, thorax, and abdomen, allowing for greater differentiation in body structure. The cephalothorax in arachnids supports the attachment of limbs and sensory organs all in one part of the body, highlighting their unique anatomical organization compared to insects.

This distinction underscores the classification within the arthropod phylum, demonstrating how these two groups have adapted to their environments in different ways. While both arachnids and insects belong to a broader group known as arthropods, their structural differences, particularly the presence of a cephalothorax in arachnids, are significant for identification and understanding their biology.