Cosmia affinis belongs to the phylum Arthropoda in the insecta class,which is the largest group in the said phylum.
Phylum: Arthropoda Class: Insecta Insects are the most diverse group of animals; they include more than a million described species and represent more than half of all known living organisms. The total number of extant species is estimated at between six and ten million; potentially over 90% of the animal life forms on Earth are insects. 
