The susceptibility of the Oahu strain of Aedes albopictus mosquitoes to infection with Dirofilaria immitis was examined to study the development of larvae in detail. Most of the developing larvae were found in the Malpighian tubules and infective larvae in the labium, indicating that Aedes albopictus Oahu strain is susceptible to the infection with D. immitis. New different patterns of development from those reported by earlier studies were observed: (i) the second-stage larvae in the thorax muscles of the mosquitoes and (ii) a small projection from the head of the sausage-form first-stage larvae.