Ill 
to seven days, at the end of which time they drop to the soil, 
pupating there (Fig. 24) about two days later within an almost 
transparent cocoon. The adult fly (Fig. 25, 26) emerges about 
six days after pupation occurs, and eggs are deposited for an¬ 
other generation of maggots. The total life cycle in summer is 
therefore about two weeks. 
As a rule the maggots do not appear in very injurious num¬ 
bers until June or July, but they have been found in rosebuds as 
early as February 22. From June until October or November, 
they are usually continuously present in such numbers as to make 
it impossible to secure a single crop of flowers. However, as 
cooler weather sets in, the injury becomes less and the maggots 
finally disappear entirely, only to reappear after the cutting of 
a single crop—or a partial one. From these facts it seems prob¬ 
able that the colder winter months are passed wholly in the dor¬ 
mant, pupal stage, in the greenhouse soil. To be sure the houses 
are heated, but their temperature in winter is only about 50° to 
55° F. at night and 55° to 65° during the day, which is 25 to 35 
degrees lower than in summer, and this is perhaps sufficiently 
low for its hibernation. 
Native roses, out-of-doors, have never, been found attacked 
by this maggot, and it is probable that, like other insects which 
are strictly greenhouse pests in the North, it is of tropical or 
subtropical origin. This probability is further strengthened by 
the fact that this species is introduced only by infested plants, 
or by the carrying of the adults by the wind from one house to 
another adjoining. The agency of the wind is apparently illus¬ 
trated by tbe following record: In one establishment the rose 
midge was introduced into the two houses farthest south in 1904; 
by 1906 the next house north was infested; and in 1907 the roses 
in two more houses to the north were attacked. In another in¬ 
stance it was noted that a clean “range,” separated from an in¬ 
fested one by a narrow passageway, became infested, and a simi¬ 
lar instance was found by Professor Webster*. 
Economic Control and Remedial Measures 
The florist should be ever on the lookout for this dangerous 
pest, for when it once becomes established in a house it is most 
difficult to combat and eradicate it, and, as in the case of many 
other insects, precaution and prevention are easier than cure. 
Only two methods are at present known to be reliable for 
thoroly eradicating the rose midge, and they require much labor 
and expense. One of these methods may properly be termed a 
*Loc. cit., p. 15 . 
