PARASITES AFFECTING THE SKIN 43 
DIPTERA AFFECTING THE SKIN. 
Besides the Aphaniptera, or fleas, already described, 
members of the Nemocera and Brachycera may attack 
animals in the réle of transitory parasites. 
The Nemocera possess long, extremely fine antenne, 
made up of six distinct segments, and are thus distin- 
guished from the flies. The larve have distinct heads. 
They include the Culicide, or mosquitoes, and the 
Simuliide, or sand-flies. 
The Brachycera are divided into the Tabanidz (breeze- 
flies) and Hippoboscide, or Pupipara. 
I. Culicide (the Mosquitoes). 
These are of more importance in human than in 
veterinary medicine, as they are the carriers of the 
organism which causes malarial fever of man. The 
females are the more important, as the males are not 
blood-suckers, but live on the juices derived by suction 
from flowers and plants. Several generations are pro- 
duced in one season. The females are fertilized by the 
males late in autumn, and then proceed to hibernate. 
In the early spring they search for a marshy spot, and 
lay their first batch of eggs in close vicinity to water. 
The larve are aquatic, and in about a fortnight they 
become pupe. A few days later the perfect insect 
emerges. 
The gnats are a well-known species, extremely com- 
mon in the neighbourhood of trees and bushes, among 
the foliage of which they rest after feeding. The 
buzzing sound caused by the rapid movement of their 
wings is only too well known. 
2. Simuliide (the Sand-Flies). 
These are often spoken of as buffalo-gnats. They are 
small and thick-set, and have not the characteristic 
