text: what is the chemicle sprayed by the mosquito before it bites? how it causes transient local anaesthesia? mosquito sprays some chemical from distance before biting so that the victim does not realize it. the effect of this chemical is only temporary. what is the nature and type of this chemical? i don't think they do use an anesthesia.  especially not one from a distance.  you usually don't feel the bite because their bite because its such a small needle.