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TWO DIPTEROUS INSECTS INJURIOUS TO CULTIVATED FLOWERS. 
By D. W. Coquillett. 
A DESTRUCTIVE LEAF-MIXER OX THE CHRYSANTHEMUM. 
Sext to the rose, there are few flowers more widely cultivated and 
admired in this country than the chrysanthemum. So great, indeed, 
is its popularity that annual fairs are held in various localities devoted en- 
tirely to an exhibition of specimens of this queenly flower. Within quite 
recent years a pest has made its 
appearance which, if not destroyed 
early in its career, will severely 
disfigure if it does not succeed in 
killing the plants outright. Xot 
only are the various kinds of 
chrysanthemums thus attacked, 
but cinerarias, eupatoriums, and 
tansy are also subject to its depre- 
dations. One grower, in trans- 
mitting specimens of the infested 
leaves to the Department, writes 
that he will be compelled to aban- 
don the growing of these plants 
owing to the attacks of this pest. 
The latter when in the adult 
state is a small, black, two-winged 
fly, represented in the accompany- 
ing engraving (Fig. 45). The front 
of the head, the face, halteres, 
knees, and posterior margin of 
each segment of the abdomen are 
yellowish. The larva, which is 
of a pale yellowish color, with the 
mouth-parts black, forms long, discolored mines in the leaves, usually 
in the blade of the leaf, but sometimes in the petiole, and passes the 
pupa state within the mine. The species was described a few years 
ago under the name of Phytomyza chrysanthemi — by Mr. Kowarz. 
The first specimens of this pest were received at this Department 
December 30, 1886, from Charles Anderson, of New York ; these were 
still in their mines in the chrysanthemum leaves, with the exception of 
two of the adults, which had issued on the way. Others put in their 
appearance at intervals up to January 10, and on the Gth of the latter 
month two were observed to be still in the larva state. 
A package of leaves of the Marguerite, or French daisy (Chrysan- 
themum fndescens), infested by this pest was received January 14, 
1887, from the well-known horticulturist, Prof. Thomas Meehan, of 
Germ an town, Fa. 
Fig. 45.— Phytomyza chrysanthemi: adult fly, 
above— enlarged ; antenna of same, to left — more 
enlarged ; leaf showing larval mines, below — natu- 
ral size; larva, at left, pupa at right— both enlarged 
(original). 
