9 
upper part of the trunk, but at the collar they occur by hundreds, so 
that they are frequently fastened one upon another. Two-thirds of the 
completed cocoon is formed by the larval case, the remainder being 
composed of new silk spun for the purpose. Before transforming, how- 
ever, the larva prepares a point of exit for the future moth by gnawing 
nearly through the wall of the cocoon at the point nearest the old place 
of exit of its head from the larval case. 
In concluding his summary of the life history of the species, M. Rou- 
zaud devotes some attention to the possibility of transporting the 
insect from one place to another. The half-grown larve are able to 
support a journey of eight days without nourishment. They will not 
destroy each other, as is the case with other carnivorous larve, but 
content themselves with gnawing the stopper which incompletely closes 
the tube and permits the access of the air. Upon their arrival they 
need only be placed upon plants infested with Coccide. During the 
entire summer it will be easier to send the larve in this way. Cocoons 
containing full-grown larve or chrysalides can also be transported in 
the same way, and will stand a journey of eight or ten days in mid- 
summer. In this case, however, it is best to wrap a few well-stocked 
twigs with gauze and inclose the cocoons in the center. If the moths 
emerge, they will couple and deposit their eggs on the journey. It is 
then only necessary to attach the twigs to those of infested trees. In 
the winter time it is easy to send the cocoons or eggs a long distance, 
and there is no reason why Erastria can not be acclimatized in Aus- 
tralia, California, and Cape Colony. 
In discussing the conditions under which Erastria may be efficaciously 
employed against Lecanium olee, there is one point of prime importance 
to be observed, says M. Rouzaud: 
It will be necessary to have at hand a sufficient number of young larve (that is to 
say, of larve which have a tolerably long life before them), and many Bark-lice for 
them to devour; to satisfy the first condition I see no way but to breed the larvee 
on a large scale. With this end in view, it would be possible to raise early larve in 
a greenhouse on bushes more advanced than those out of doors, and subsequently 
to carry these larve to an infested plant. It might even be possible to discover an 
animal nourishment which would suffice for a sort of artificial feeding of the young 
larve. I believe that oleanders suitably forced towards the end of the winter 
and well stocked the preceding summer with young Lecanium olew could be readily 
used in the production of early larve of Erastria onalargescale. But I also believe 
that a true artificial food may be found for them, easier to produce and distribute 
than living prey. In either case, of course, everything is yet to be done and the 
field is open for research; the end to be attained seems to me worthy of the most 
skillful experimenters. Admitting that a sufficient quantity of the larvx are at 
hand, and that the problem of rearing them on a large scale has been solved, a sec- 
ond very important point to be observed is, that they shall be put to work at the 
right moment, say just before the eggs are laid by the Bark-lice, or at least before 
the issuance and spread of the young. 
In sending us copies of the important paper which we have thus 
reviewed, M. Rouzaud has kindly offered to transport to this country 
