This creature is inspired by Diablo 3. What CR would you put it at?
Sand Wasp
N Medium Vermin
Init +4; Senses Darkvision; Perception +10
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DEFENSE
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AC 18, touch 14, flat-footed 14 (+4 Dex, +4 natural)
hp 39 (6d8+12)
Fort +8, Ref +6, Will +4
Immune mind-affecting
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OFFENSE
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Spd 10 ft., Fly 60 ft. (Good)
Melee Sting +4 1d4 plus poison
Ranged 1d3 Wasps +8 (touch) poison
Space 5 ft.; Reach 5 ft.
Special Attacks Poison - contact (DC 19)
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STATISTICS
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Str 10, Dex 19, Con 16, Int -, Wis 14, Cha 11
BAB +4; CMB +4; CMD 19
Feats Hover, Flyby Attack
Skills Fly +8, Perception +10, Stealth +4
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SPECIAL ABILITIES
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Poison: Sting - contact (DC 19) (Ex) Poison deals 1d3 CON damage, 1/round for 6 rds, cure 1 save.
Wasps: A Sand Wasp carries hundreds of eggs ready to be hatched in its gullet. As a standard action, it can hatch and spit the baby wasps at anything that threatens it. This is a ranged touch attack with a maximum range of 30 feet. Enemies hit by this attack are subjected to the Sand Wasp's poison.
Build question - is your intent to give the sand wasp Hover and Flyby Attack as bonus feats?
Also, is it getting some sort of racial bonus to perception?
Yes, and yes. It receives a +8 racial modifier to Perception (the creature is based a great deal on a Giant Wasp).
This creature is inspired by Diablo 3. What CR would you put it at?
About CR 50 on Inferno :P
On a more serious note:
Ranged 1d3 Wasps +8 (touch) poison
Was your intention here that the target takes 1d3 damage, or that the target is struck by 1d3 wasps (and if so, does that mean the target is saving against the poison 1d3 times)?