152 
Journal of Agricultural Research 
Vol. XXIX, No. & 
As may be observed in Table VIII 
nine distinct generations were reared 
during 1921, indicating that there may 
be a definite overlapping of genera¬ 
tions throughout the year under green¬ 
house conditions. The first seven 
moths, which began emerging January 
17 from nearly full-grown larvae 
received January 5, were considered 
as completing a partial first generation. 
Twenty-three adults of the second 
generation began appearing March 4. 
The life cycle of 73 moths was observed 
during the third generation and the 
first individuals emerged on April 15. 
Observations on the fourth, fifth, and 
sixth generations were made on speci¬ 
mens reared under normal greenhouse 
conditions because the high tempera¬ 
tures prevailing during June, July, 
and August made it difficult to rear 
them in cages. The first adults of the 
seventh, eighth, and ninth broods 
appeared on the following dates: 
September 14, October 24, and Decem¬ 
ber 2, with totals of 78, 23, and 26 
specimens, respectively. The time be¬ 
tween emergence of the first adults of 
the ninth generation and January 5 
of the ensuing year would allow suf¬ 
ficient time for the completion of the 
partial first generation mentioned 
above. Like other insect pests which 
live both indoors and outdoors, the 
greenhouse leaf-tyer apparently flour¬ 
ishes best under glass during the winter 
and spring months, at which time its 
depredations are most frequently re¬ 
ported. In the summer months it 
causes serious injury outdoors on 
truck and garden crops, especially on 
celery, beets, and lettuce. 
NATURAL ENEMIES 
In the course of these life-history 
studies, spiders and ants proved to be 
important enemies of Phlyctaenia rubi- 
galis. Small spiders of the species 
Theridium tepidariorum Koch, which 
conceal themselves along the sides of 
the flowerpots, or even on the leaves of 
infested plants, confined their attention 
to destroying the larvae and adults, 
while the pupae were apparently un¬ 
molested. The spider first renders its 
victim helpless by entangling it with a 
few strands of webbing and then 
puncturing it and later sucking the 
entire body contents. 
The small red ant sometimes called 
Pharaoh’s ant, Monomorium pharaonis 
L., was not observed to disturb the eggs 
but attacked all other stages, being 
especially destructive to the pupae and 
moths. These ants chewed the pupae 
into bits and devoured them, and not. 
only ate the bodies of the moths, but- 
even carried away pieces of the wings. 
No insect parasites were reared from 
any of the material used in these 
experiments, but the following natural 
enemies have been recorded as occurring 
in the United States: 
Chittenden (3, p. 19) says: “A single 
parasite of this species has been ob¬ 
served, the only natural enemy that 
appears to be known for it. Among 
a lot of larvae from Livonia, Pa., a 
cocoon was found May 19, which gave 
the imago May 27. It was identified 
by Mr. Ashmead as a species of Syne- 
taeris, an ichneumonid genus related to 
Limneiia.” 
J. J. Davis ( 4, p • 100) reports: “A 
hymenopterous parasite of this leaf- 
tier was common in the greenhouses of 
Chicago, and no doubt in many of 
them it was doing much to hold the- 
leaf-tier in check. The species was- 
determined by Chas. T. Brues as 
Apanteles glomeratus Linn. A tachini d 
fly bred from this leaf-tier was deter¬ 
mined by C. A. Hart as Phorocerit 
parva Bigot.” 
According to Gibson (6, p. 629) no¬ 
parasites were reared from Canadian 
material. 
CONTROL 
Since a review of published records 
and recent correspondence relating to 
this pest indicates that none of the 
recommendations for control have 
proved entirely satisfactory, experi¬ 
mental work was conducted that 
further data on this subject might be 
obtained. These tests included fumi¬ 
gation with hydrocyanic-acid gas and 
dipping, spraying, or dusting with in¬ 
secticides. 
FUMIGATION WITH HYDROCYANIC-ACII> 
GAS 
Although some writers have sug¬ 
gested the use of hydrocyanic-acid gas, 
its use has generally been discouraged 
because burning of the tender growth 
frequently has accompanied such treat¬ 
ment when employed at sufficient con¬ 
centration to kill the moths. Recent- 
experience, however (12), indicates that 
although slight temporary injury may 
occur on such plants as jasmine, ager- 
atum, German ivy, chrysanthemum 
marguerite, salvia, geranium, dahlia,, 
cestrum, heliotrope, and stephanandra,. 
no permanent injury will result. In 
the case of violets, Chittenden (3, p. 20} 
recommends it as a most satisfactory 
remedy, but he also says that “it can 
not yet be safely used for the fumiga- 
