(Figure 5-46)

This group is also known by the common name of biting gnats or sand flys. The bite of the fly produces a lesion with a wheal that may be 1 to 2 cm in diameter. These flies have mouthparts that unlike the mosquito tear a small hole in the skin from which they lap up blood and tissue fluids. There are a number of genera in this group, but only Culicoides, Leptoconops, Forcipomyia, and Austroconops are considered as regularly feeding on mammals; most of the other species feed on insects or reptiles and amphibia.

The fly is characterized by being small (less than a mm long) and dark with long delicate antennae. The wings tend to be narrow and are folded flat over the body when the fly is feeding. The wings often appear spotted when examined closely (Fig. 5-46).

Eggs are laid in tree holes, decaying vegetation in water, surface of wet sand, manure, aquatic plants, or leaf mold. Some prefer salt water. The larvae are maggot-like. The pupa is elongate and has a pair of long thracic breathing trumpets.

It is likely that cats are affected by the bites of these flies in a fashion similar to humans, but there seem to be no descriptions of the effects of these bites on humans. The bite of a Culicoides has been associated with the transmission of a filarid nematode parasite of the raccoon, Tetrapetalonemallewellyni which was discovered in the microfilarial stage in the blood of a cat in Switzerland.


Gafner F, Hörning B. 1988. Mikrofilarien bein einer Katze. Schweiz Arch Tierheilk 130:651-654.

Figure 5-46. Culicoides. Note the short and stocky mouthparts and the motled wings.