74 
EXTRACTS FROM CORRESPONDENCE. 
Fertilization of Yucca in Australia. 
Having read several of your letters relating to the pollinization of Yucca by Pro- 
nuba species exclusively, I understand why the plants have no fruit here where else 
they grow extremely well. However, either some of the Pronubas have been intro- 
duced here, of which I have no information, or else some native moth has adapted 
itself to the function, for on November 11, 1889, while on a visit to our Agricultural 
College at Roseworthy with the Field Naturalist Section of the Royal Society of 
South Australia, I noticed fruitsin abundance on a tree in the garden of the director, 
Professor Lowrie, to which I drew the attention of several of the party at the time 
and also afterwards mentioned the fact in the Royal Society. As my office duties 
prevented my making observations personally at a distant locality, nothing further 
has been learned about the subject since. AsI thought the matter might interest 
you, I inclose the only fruit secured at the time. * * *—[{J.G.O. Tepper, Curator 
of Insects, Somerset Place, Norwood, South Australia, May 11, 1890. 
REPLY.—I am very much obliged to you for your kindness in sending me the Yucca 
pod accompanying your favor of the 11th ultimo. * * * The Yucca pod showed no 
trace of Pronuba and the fertilization of the plant must be explained on the same ex- 
ceptional grounds on which I have already explained similar pollinization of Yucca in 
other countries where Pronuba can scarcely occur. The pod, though very much shriv- 
eled, shows it to belong to the aloifolia section of the genus, but without a know- 
ledge of the leaf and flower it would be risky to decide specifically. I shall be very 
much obliged to you if you ean at some future time send a larger supply, since it 
frequently happens, even where Pronuba occurs, that the pods are free from its larva.— 
[June 16, 1890, ] 
A New Sawfly Enemy to Sweet Potatoes. 
I have sent you by to-day’s mail a box containing some flies and their eggs on some 
sweet potato leaves. Last year was the first time they made their appearance in my 
potato patch. They came the 1st of July and deposited their eggs on the leaves; 
when the eggs hatched these worms would eat the leaves to a comb. This con- 
tinued for about 4 weeks. The potatoes, wherever the fly was, did not make any 
yield at all. This year the fly made its appearance at the same time they did last 
year. Will you please tell me what kind of a fly they are, and whether they will do 
any serious damage ?—[George W. Stockley, Keller, Virginia, July 2, 1891. 
REPLY.—The insect which you send is entirely new as an.enemy of the Sweet Po- 
tato. It isa sawfly known scientifically as Schizocerus privatus. Some 5 years ago 
another species of the same genus was discovered feeding upon Sweet Potato at Ocean 
Springs, Mississippi. You will find it described on page 44 of no. 2, vol. 1, of INSECT 
Lire. Should this insect become very abundant it can be readily killed by the appli- 
cation of Paris green in the proportion of one-fourth of a pound of the poison to forty 
gallons of water. It is hardly likely, however, that it will prove to be much of a 
pest.—[July 8, 1891. ] 
Injurious Insects of Utah. 
Utah is certainly amost unfavorable place to make observations in economic ento- 
mology, for there are neither grasshoppers nor crickets here this year. There is only 
one important insect enemy visible at the present season, viz, that Tent-caterpillar 
which has been sent to you on several occasions from this Territory. I failed to see 
it in Salt Lake City, as well as near Mill Creek, which is in the center of the lower 
cultivated (i. e., irrigated) area of Utah. I saw it first at Park City at an altitude 
