A couple of weeks ago, I took this picture of what I thought was a Western Tiger Swallowtail. I tried to confirm the ID by comparing it to the many photos on file at BugGuide. Turned out none of the WTS butterflies have this much black on them. In fact I couldn't find any swallowtails that matched exactly.


A normal Western Tiger Swallowtail butterfly photographed by Ron Hemberger


So I posted it to BugGuide, and little by little, the experts are weighing in with their opinions about this butterfly. I agree that it looks like an aberrant WTS. And now I will pass along my vocabulary lesson for today

aberrant

Pronunciation: \a-ˈber-ənt, ə-, -ˈbe-rənt; ˈa-bə-rənt, -ˌber-ənt, -ˌbe-rənt\
Function: adjective
Etymology: Latin aberrant-, aberrans, present participle of aberrare to go astray, from ab- + errare to wander, err
Date: circa 1780
1 : straying from the right or normal way

2 : deviating from the usual or natural type : atypical



courtesy of Merriam-Webster online