I have been looking for a morphological difference between Oc. triseriatus and Oc. hendersoni and the only difference I can find in the literature is the shape of the tarsal claws and one structure called the acus in the larval stage (Reno et al., 2000). Do you have any information on the ranges of these two species or some other morphological difference between them? Some of my resesearch focuses on LaCrosse encephalitis virus (transmitted by Oc. triseriatus but not Oc. hendersoni), so I would really appreciate your input on this.

Hard to be sure which this is from this picture (we actually use PCR to be sure these days sometimes) but I think this might be triseriatus. The black band on hendersoni is typically thinner near the head than it is on triseriatus. However without two reference samples this is a very poor method of distinguishing the two species for certain, but perhaps I mistaken.

As to ranges, tris and hendersoni occupy most of the eastern United States together (though there may be vertical stratification of larval habitats). A bit west of the Mississippi, you can find hendersoni alone in some places, and you can find triseriatus alone in some areas of Florida (maybe Maine too). We very rarely find hendersoni in larval collections near ground level in Mass., but we will find them about a meter off the ground. Adults have been found biting on the forest floor.

I do not have any info on these species. I was having Omar do these, since I have never worked in the Northeast. This one looked very much like what he ID'ed as hendersoni.

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