Rosemary oil is helpful in repelling not only mosquitoes but also biting flies, and it smells really nice. Eucalyptus oil is good for repelling TICKS! Even Vicks Vapo rub works great. Put it on your feet and legs and if in the woods, your pantlegs and shoes also, to keep ticks away. I have experimented with this at length--I live in the woods, and just walking 20 feet to the car its common to pick up at least ten! I even put a live tick in the sink, in the center of a ring of vicks, and the tick walked to the line and backed away, over and over. It didn't want to cross the line. They breathe through their exoskeletons, and it overwhelms them. If they get it on them, they DIE.
Eucalyptus is also very calming--I began to use it a lot as aromatherapy (I HUFF it, essentially!) when I was quitting smoking. I still do--now the craving for cigarettes has been replaced by a craving for eucalyptus! I discovered in a number of self tests that it lowers my blood pressure an average of 20 points after inhalation!!!! I took readings before and after, and it came down every time.