Your Dexterity score increases by 2, and your Wisdom score increases by 1.

Arachne, much like spiders, mature quickly, becoming adults at the age of 2 or 3 and having lifespans comparable to elves'.

Webbing. You can cast the spell web once per short or long rest.  Wisdom is your spellcasting ability for this spell. Once you do so, you can't cast it again until you finish a short or long rest.   Each short or long rest you regain three webbing charges, you can create traps with your webbing, each webbing action consumes 1 charge of webbing.

• When a target is restrained by webs, they are restrained. A webbed creature can use its action to attempt a DC 12 Str (Athletics) check to escape. The web can also be destroyed by 5 points of slashing or fire damage against AC 10.

Spider Walk. You have a climb speed equal to your walking speed. You can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check. Additionally, you ignore movement restrictions caused by webbing.

Venom Glands. Once per short rest as an action, you excrete venom onto your fangs and weapons, until combat ends, your melee attacks do an additional 1d4 acid damage, add another 1d4 acid damage for each level

Tremorsense.  You have tremorsense for 60ft due to tiny hairs on your spider half

You can speak, read, and write Common, Spydric and Undercommon. 

Arachne's knowledge of poisons gives them a resistance to Poison.