I just stumbled on the column on gnat swarming. The explanation of swarming is reasonably accurate. However, the mention of “Trypetidae” as gnats is completely wrong. Among entomologists, “gnat” universally refers to flies of the group Nematocera, most of which are shaped something like a mosquito. Fruit flies, on the other hand, belong to the group Cyclorrhapha, most of which are shaped something like a house fly. It’s like getting cats mixed up with bears, or pine trees mixed up with junipers. Many gnats do swarm over or under a “fixed” point, as described here. Fruit flies do not.
Another error: the name “Trypetidae” is obsolete. It was officially replaced by the name Tephritidae around 1965. Tephritids are true fruit flies many of which infest living fruit and are serious pests to fruit growers. Drosophilids, on the other hand, are the “fruit flies” of the geneticist and breed only in dead, fermenting fruit. Common names are slippery things.
Interesting factoid: gnat swarms can also use a “fixed point” that is not fixed, e.g. you can have a swarm over your head as you saunter along beside a lake in the evening dusk, whcih will follow you along and remain over your head. If this happens to a couple, the swarm will divide when the two people go their separate ways.
Should anyone wonder how I dare question the word of the Great Cecil, I happen to be the one person who answers nearly all the “bug questions” that come to a large university. Therefore, on this particular subject I dare almost anything.
Here’s a syllogism for you:
Major premise: Cecil Adams never makes a mistake.
Minor premise: There are 2 mistakes in this column.
Conclusion: This column is a forgery, not really written by Cecil.