DIPTERA (TWO-WINGED FLIES). 
75 
BIBIO MARCI, 
WITH HEAD OF 
The white grubs of the Fungus-midges (Mycetophilidce) have 
black heads, and are to be found for the most part in fungi and 
boleti. 
The larvae of Bibionidce — a family that in- 
cludes " St. Mark's fly " (Bibio marci, L.) and 
other species of black flies, which in England 
are exceedingly common in meadows in spring 
and early summer, sometimes hovering in the 
air, dancing in swarms, or feeding on the heads 
of Compositae — are similar in appearance, and 
may be met with in vegetable mould, or in the 
droppings of cattle. 
The greenish, somewhat leech-like larvae of the Simulidce — a 
family that includes a number of blood-sucking species — may be 
found (with the pupae) in brooks and streams, adhering to the sub- 
merged stems of rushes and other water plants. 
The mode of life of the larvae of the true Midges (Chirono- 
midm) is somewhat varied, those of the genus 
Chironomus being aquatic or living in the soil 
or in droppings (the well-known " blood-worm," 
so common in rain-water, is the larva of 
Chironomus plumosus, L.) ; the larvae of the 
genus Ceratopogon, which includes a number of 
blood-sucking Midges, are found under the bark 
of trees and in decaying vegetable matter ; the larvae of Clunio 
are marine, living in rock-pools and feeding on green sea-weed 
(Cladophorob). 
The exceedingly active larvae and pupae of 
Gnats or Mosquitoes (Cidicidce) are exclusively 
aquatic, and are to be found in ponds, tanks, or 
butts of rain-water, and also in open drains and 
cess-pools : in the tropics, in casual accumula- 
tions of water in old tins, bottles, calabashes, 
etc. (genus Cidex), or in stagnant or nearly 
stagnant water in pools, at the side of slowly 
flowing streams, or in permanent puddles 
anopheles maculipennis. (genus Anopheles). 
