This European species, variously known as
the Essex Skipper or the European Skipper, was first noticed in North America
near London, Ontario, and was noticed in the Victoria area by Gordon Hart and
Mark Carson in 1992 and identified in 1994 by Stephen Ansell.
This is the only Thymelicus in our area, so identification is not a problem, but in Europe it has to be distinguished from a similar species, T. sylvestris. The main difference usually cited is that the underside of the tip of the antenna is black in lineola and orange in sylvestris - about as fine a distinction as one is likely to come across. I therefore tried to photograph the underside of the tip of the antenna, and indeed it is black and surprisingly distinctive.
Here, it need be distinguished only from Ochlodes sylvanoides. Apart from the different markings, lineola is an obviously smaller butterfly, and is to be seen in June, whereas we usually have to wait until July and August for sylvanoides.
The caterpillar has a reputation for preferring the grass Phleum, although I have searched diligently on this grass and have never found the caterpillar. I have found it on the grasses Dactylus, Bromus, Holcus and, especially, Phalaris. I suspect that it is not very particular about which grass it chooses and that it has no special preference for Phleum.