594 
DIPTERA. 
or milk ; and this statement agrees with the observations of 
Mrs. Gage. 
The flies are not confined to wheat alone, but deposit in 
barley, rye, and oats, when these plants are in flower at the 
time of their appearance. I have found the maggots within 
the seed-scales of grass, growing near to wheat-fields. The 
eggs hatch in about eight days after they are laid, when the 
little yellow maggots or grain-worms may be found within 
the chaffy scales of the grain. Being hatched at various 
times during a period of four or five weeks, they do not all 
arrive at maturity together. Mrs. Gage informs me that 
they appear to come to their growth in twelve or fourteen 
days. They do not exceed one eighth of an inch in length, 
and many, even when fully grown, are much smaller. From 
two to fifteen or twenty have been found within the husk of 
a single grain, and sometimes in every husk in the ear. In 
warm and sheltered situations, and in parts of fields pioteet- 
ed from the wind by fences, buddings, trees, or bushes, the 
insects are said to be much more numerous than in fields 
upon high ground or other exposed places, where the giain 
is kept in constant motion by the wind. Grain is commonly 
more infested by them during the second than the fiist yeai, 
when grown on the same ground two years in succession; 
and it suffers more in the immediate vicinity of old fields, 
than in places more remote. These insects prey on the 
wheat in the milky state, and their ravages cease when the 
grain becomes hard. They do not burrow within the ker- 
nels, but live on the pollen and on the soft matter of the 
grain, which they probably extract from the base of the 
germs. 
It appears, from various statements, that very early and 
very late wheat escape with comparatively little injury ; the 
amount of which, in other cases, depends upon the condition 
of the grain at the time when the maggots are hatched. 
When the maggots begin their depredations soon after the 
blossoming of the grain, they do the greatest injury ; for the 
