403 
abundant were Dakruina larva- in the District of Columbia in the sea- 
son of 1879 that it is quite probable the freedom of the Washing- 
ton maples from this destructive scale since that time has been due in 
large measure to this Dakruma. Later the insect was found to feed 
in a similar manner upon other large scale insects of the Subfamily 
Lecaniime, and particularly upon the largest of our native species, 
Leeanium tulipiferce Cook, which frequently occurs in enormous num- 
bers upon the tulip tree and upon different species of Magnolia in the 
South. 
The Dakruma larva, as is well known, leads a hidden existence. It 
works beueath the bodies of the scale insects, eating them out, one 
after another, from below. When the scales are crowded upon a twig 
or branch, the Dakruma larva passes from one to another without show- 
ing any indication of its presence. Where the scales are more scat- 
tered, and some little distance intervenes between them, the Dakruma 
larva still hides itself, traversing the open spaces within a delicate 
silken tube which it spins as it goes. It is thus protected from ordinary 
natural enemies, and no parasite has hitherto been known to affect it. 
It has not, however, escaped the notice of one of the omnipresent and 
apparently sharp-eyed chalcidids. There was brought me recently from 
the insectary a series of little parasites which had been reared, so the 
labels stated, from a mass of specimens of Leeanium tulipiferce upon a 
Magnolia tree, ^hich had been sent up from Florida by Mr. Hubbard. 
The labeler suprjosed that he had before him a new parasite of the 
Leeanium. A glance at the specimen, however, showed that the para- 
site belonged to the subfamily Elachistinae, the species of which are, 
so far as we know, invariably parasitic upon lepidopterous larva?. An 
examination of the specimens of Leeanium from which the parasites 
were supposed to have been reared was immediately made, and they 
were found, upon lifting them from the twig, to have been eaten out by 
the larva of the Dakruma, and from the Dakruma larva, not from the 
scale insects, came the little parasites. 
This observation is of interest, in the first place, as indicating that 
the Dakruma larva, with all its care, has not succeeded in hiding itself 
from its natural enemies. In the second place, it emphasizes once more 
the necessity for the most careful consideration of all the circumstances 
in recording the host relations of parasitic insects, and forms perhaps 
a more striking example of this necessity than any of those mentioned 
by the writer in an article upon this subject published in Insect Life 
(vol. iv, pp. 48, 49). In the third place, the observation is of system- 
atic interest, since the insect reared forms the type of a new genus. Its 
characterization follows : 
LEUCODESMIA n. gen. 
Female: Resembles Stenomeziun AVcstwood. Abdomen with a distinct, though 
very short, petiole; scutellum with two longitudinal impressed lines: posterior 
tibia- with one short spur: prothorax subcorneal ; wings broad. Head broad and 
well rounded, shrinking very considerably, however, in death. Ocelli forming a 
