On our regional range maps, we color in entire states and provinces, and similarly, our West Virginia range maps color in entire counties. This can sometimes be misleading, especially in the largest states and counties, where the particular insect species may live in only a part of the area that is colored in. In the cases of large provinces such as Ontario and Quebec, it is often the case that the insect species in question lives in only the far southern part of the province, and the insect is not as cold-tolerant as a glance at the map might suggest.

Under-collecting in many states, provinces, and counties can also make the range maps misleading. The fact that a geographic subdivision isn't colored in on the map may signify that the species doesn’t live in that area, or alternatively that the insect species does live there but has not yet been collected and reported.

On the regional maps, West Virginia is colored in for a particular species based on the fact that we have photographed the species in West Virginia. In some cases, there are also published records from the state of West Virginia.

On both the regional maps and the West Virginia maps, the green-blue color signifies areas that have reported the species.

Our counties, states, and provinces page features maps that includes the names of those subdivisions, which may prove helpful since our other maps do label the counties and other subdivisions.

In the case of flies, we compiled data based on the books and articles cited in our Works Consulted page for Diptera. Revisions of genera and subfamilies often gave extensive lists of records of each species. State-specific books and articles also provided range information. For West Virginia, one publication that was especially useful for one family was Horse Flies and Deer Flies of West Virginia: An Illustrated Key, by Drees, Butler, and Pechuman (1980).

On-line sources have also been quite useful. Many public insect collections are providing their collection data on-line. Three especially good sites that are adjuncts to traditional pinned collections are: The Canadian National Collection; Harvard's Museum of Comparative Zoology; and the University of New Hampshire Insect and Arachnid Collections, the latter under the leadership of Donald Chandler. BugGuide includes photos with date and place information. Stand-alone sites specializing in the insects of a particular state or province (like this one!) are becoming more common, for example Les Insectes du Québec, and these have also served as sources for our range maps.

We would be glad to hear of corrections and additions to the information shown on the maps. To keep the maps as accurate as possible, new range information should be based on a determination by a professional entomologist or other subject expert, or based on a publicly accessible photographic record. For the latter, the best place to file such a record is BugGuide.net, where typically dozens of people check the accuracy of the identification.