Scale pattern variations of Aedes aegypti in Chiang Mai, northern Thailand.

Abdominal tergal scale pattern variations of Aedes aegypti were studied in Chiang Mai, northern Thailand for specimens reared from eggs laid in ovitraps set monthly both indoors and outdoors in urban and rural areas. The populations predominantly consisted of the dark type form, regardless of macrohabitats (urban vs. rural), microhabitats (indoor vs. outdoor) or seasons (dry vs. rainy). Among 6,003 specimens, no individuals had pale-scales continuing from the tergal base to its apex on the third tergum and posteriorly.