|Common Blue (Polyommatus icarus) male. (by-nc-nd)|
|Common Blue (Polyommatus icarus) female. (by-nc-nd)|
|Common Blue (Polyommatus icarus) male on a yellow flower. (by-nc-nd)|
Colias croceus is a small butterfly of the Pieridae family, that is, the Yellows and Whites. In most places it is simply known as "the clouded yellow".
The Common Clouded Yellow's breeding range is North Africa, southern Europe, and eastwards through Turkey into the Middle East, but it's common throughout much of Europe as a summer migrant, in good years individuals reaching even Scandinavia.
|Common Clouded Yellow (Colias croceus) butterfly. (by-nc-nd)|
Obviously this isn't a butterfly, but the colours match the colour palette of the other images — all the insects sit on yellow flowers.