BEHAVIOR:

EMERGENCE:

Larva molt 6-9 times before pupating
These instar larva are developing visibly under the cuticle of the thorax
Metamorphosis (topipal stage) occurs with in the body of the larva
The adult pulls it self through a T-shaped slit in the dorsum of the pupal skin and rises to the surface in a bubble of air
It then sits on vegetation until body hardens
The community of black flies occur in a mass, synchronized hatch
(Williams et al., 1992, pg. 89)
Univoltine, bivoltine, multivoltine
(Thorp, 1991 pg.628)

Varies from 1-2 eggs being deposited to strings of eggs (0.2-0.46mm long) being attached to submerged rocks or floating substrates while the abdomen of the female touches the waters surface
The hatch is any where from 4-30 days
(Williams et al., 1992 pg 93)
Eggs are laid at sunset
The synchronous hatch of the blood -suckers is very dangerous to mammals
Oviposition is variable some deposit eggs over water some deposit eggs on wet vegetation along shoreline
Usually 200-500 eggs are laid and larvae go through 6-7 instars
Incubation is 4-30 day depending on species and environmental condition
First instar has a spine on the head (egg burster) that allows larva to escape
Larval life span usually 6-7 months long overwinter as larvae or eggs
Those as larvae may have significant growth during the winter, indicating metabolic activity pupation at site of larval attachment
Last larval instar spins a cocoon with an air bubble that is anchored and protects the pupa pupal period 4-7 days long
Adult emerges from a slit in the cocoon
The wings expand and the fly rises to the surface on the air bubble and flies away
Many species are univoltine, bivoltine or multivoltine
(http://www.biology.eku.edu/SCHUSTER/bio%20806/diptera.htm)
Female requires a blood meal for maturation of eggs
(Thorp, 1991 pg.628)

Larva and pupae attach themselves to firm, smooth substrates with hooks and move by
ÔmountaineeringÕ, a technique using silk and loops
(Williams et al., 1992 pg 89)