Abstract: This experiment aims at understanding the morphological differences between the venom glands of the Mygalomorphae and Araneomorphae, and to provide a reference for future study of the evolution and morphology of spider venom glands. In this experiment, four species of Mygalomorphae and four spiders of Araneomorphae were selected for observation and comparison of the size, location, external morphological characteristics, and internal structure of their venom glands. The results showed that the venom glands of the Araneomorphae are usually located in the prosoma and are distributed symmetrically, while those of the Mygalomorphae are usually located in the chelicera; they have ducts in the apex and extension from the prosoma or chelicera to the fang, The free ends of the former are blunt and round without ducts, and the venom glands of the latter have tapered ends that are elongated and tapered back, creating a cord-like structure; Different species of spider venom glands vary in size and shape; Observation of the internal structure of the venom gland showed that the glandular cavities of the Mygalomorphae were more numerous and compact, and the glandular cavities of the Araneomorphae were less and loose. To a certain extent, this result indicates that the position change and morphological structure of spider venom glands may be related to the evolution of spider venom glands.

Key words: spider venom gland, Mygalomorphae, Araneomorphae, morphology