properly identified) is seen to extend far back into the abdomen, much 
farther than with Bugnion's Encyrtns. 
The insects of this subfamily are all, so far as we know, parasitic 
either upon the Coccidae, Aleyrodida}, or Aphididae. They are evidently 
many-brooded, and issue from their hosts indifferently throughout the 
warmer months of the year, and through the winter in the insectary. 
With the Aleyrodidae, Aphididae, and the Diaspinae among the Coccidae, 
but one specimen, apparently, issues from a single host insect. With 
the larger naked scale insects, however, several parasites may issue 
from a single host. Sufficient observations have not been made upon 
the early stages of the Aphelininae. Their larvae feed both upon the 
body of the scale insect and upon the eggs. They attack both sexes 
of the host, issuing when full grown through circular holes cut through 
the body walls, and, in the case of the Diaspinae, through the scale. 
With the scale insects of the genus Pulvinaria, the aphelinine larvae 
live within the body of the female and not in the waxy egg mass which 
she secretes. 
Economically, the Aphelininae are by far the most important of the 
parasites of the Diaspinae. Other scale insects are more abundantly 
parasitized by species of other groups, notably the Encyrtime, but with 
the Diaspinae it is really difficult to find an affected tree which does 
not bear scales pierced by the exit holes of some aphelinine. It was 
with a species of the genus Aphelinus that LeBaron made the first 
attempt at the transportation of a scale parasite from one region to 
another in which the parasite was supposed not to occur. As a matter 
of fact, however, while the numbers of the Diaspinae are undoubtedly 
frequently reduced to a considerable extent by the work of the mem- 
bers of this subfamily, I have never seen a plant affected by scale 
insects in which the Ooccidae were even approximately exterminated 
by these insects. Tbe claims which were at one time made in Cali- 
fornia of the extraordinarily beneficial work of Aspidiotiphagus citrinus 
upon Aspidiotus aurantii have always seemed to me unjustified, and in 
this opinion I am supported by the evidence of Mr. D. W. Coquillett, 
who states that upon personal examination of the orchard in which it 
was claimed that this parasite had nearly exterminated the scale he 
found that but a small proportion of the dead scale insects contained 
the issuing holes of the parasites. The great majority of them seemed 
to have been killed by some disease. 
The larvae of the early generations of tbe species of the genus Aplie- 
linuSj as may be inferred from what I have said in the previous para- 
graph, feed upon the body of the scale insect, but those of the late 
generations feed upon the eggs. Confirmatory evidence of the incom- 
pleteness of the work of the species of Aphelinus has been gained by 
the careful examination in the early spring of a large number of scales 
of Mytilaspis pomorum parasitized by Aphelinus mytilaspidis. Under 
