1948] 
Bailey — Tabanus atratus 
135 
there laid another little batch on the inside of the box. 
Very few of these eggs produced larvae. 
The other female was handled in the same manner. 
The form of her egg mass was not unusual, but she ap- 
parently lost her sense of direction in the darkness of the 
container and laid the rest of her eggs in a neat pattern 
well below the others and with her head up, facing them. 
This final batch was stacked in four tiers and was, con- 
sequently higher than usual. 
Hine (1903) stated that, “Between nine o’clock and 
noon seems to be the favorite time of day for oviposition 
with the various species of both Chrysops and Tabanus, 
and I have seldom been able to observe females oviposit- 
ing at other hours of the day.” My own observations for 
nantuckensis are just the reverse. All ovipositing was 
seen in the afternoon — from just after 12 until 5 p.m. 
However, Cameron (1926) is probably justified in saying 
that oviposition may take place at any time between 8 
a.m. and 5 p.m. on bright days in June and July — and, I 
would add, in August. It is very likely that there is some 
such activity in the morning on the saltmarsh, but cer- 
tainly it is not restricted to the forenoon hours in Essex 
County. 
The incubation period was obtained for three egg mas- 
ses. Hatching occurred in the early morning in one in- 
. stance and probably at that time of day in the others. A 
mass deposited on August 19th hatched on August 26th 
after an incubation of seven days. The other two, laid 
August 27tli and 29th, hatched on September 5th and 7th 
respectively after incubating 9 days. In each case the 
blade of grass was stuck into sand in a pint jar. Water 
covered the sand to a depth of half an inch and the eggs 
were at a level just below the rim of the uncovered jar in 
a relatively moist atmosphere. However, the containers 
were kept indoors and this probably lengthened the in- 
cubation period appreciably. The 7 and 9 day periods 
correspond with those similarly obtained by Hart (1895) 
and by Hine (1906), in that order, for T. atratus Fabri- 
cius, while Schwardt noted a 5 day period for eggs of 
this species in an outdoor insectary in Arkansas. Full 
sunlight undoubtedly hastens development. 
