LIBRARY

336 COLLEGE ENTOMOLOGY
Mounting. - Aphids should be thoroughly cleared and the nonpigmented
forms stained for study. This necessitates a considerable technique and
skill. The old method of mounting directly into balsam or euparal renders
the specimens almost useless for microscopic examination.
Temporary mounts. - Very good temporary mounts for immediate study
may be made by mounting living or fresh specimens directly into the
so-called Faure, Berlese, or chloral hydrate-gum arabic mixtures. After
arranging the specimens and completing the mount the slides should
be placed in a warming oven at 120°F for 1 hour to permit clearing,
inflation, and to seal the cover glass. Subsequent ringing with a suitable
cement like "Murryite" may prolong the life of the slides. In
case of crystallization or deterioration the specimens may be removed
and remounted.
Permanent mounts may be made according to several methods, of which
two are recommended:
1. Caustic Potash. - Fresh specimens or those preserved in alcohol
or formalin or dried are immersed directly in a 10 per cent solution
of KOH (or NaOH) and placed in a warming oven, boiled
over a flame, or set aside in closed containers and will soon become
relaxed and cleared. Embryos should be removed even
though cleared if the specimens are to be stained. Transfer to
full-strength acetic acid, tease or press out KOH solutions, and
remove to fresh acetic acid for 10 minutes. They may be stained
in this solution by adding acid fuchsin or alcoholic fast green
or other stain. Remove to clove oil for 5 minutes. Transfer
directly into canada balsam from one to five or six specimens,
including various forms stained or unstained. Place cover glass.
2. Lactic Acid. - Fresh specimens or those preserved in alcohol or
other preservative are removed to a solution composed of lactic
acid 50 parts, 95 per cent alcohol 35 parts, and water 15 parts.
Set in a closed dish in a warming oven at 120°F for 24 hours for
fresh specimens to 48 hours for preserved ones. Tease out embryos.
Stain if necessary. Transfer to acetic acid, then to clove
oil, and mount in balsam; or transfer to 95 per cent and absolute
alcohol, then to clove oil, and mount either in balsam or euparal.
Many fossil remains of aphids have been found despite the small size and
delicate structure of these insects. The oldest known fossil is Canadaphis carpenteri
Essig (1937) taken in Cretaceous Canadian Amber. It has the aphid.
type wings showing the greatest development in venation, six-segmented
antennre with apical filament or spur, tuberculate eyes, and two-segmented
tarsi with a pair of claws. Numbers of specimens have been taken in Oligocene
Baltic Amber and in the shales of Florissant, Colo.
The family is widely distributed in the temperate regions of the world 1
I There is but a single indigenous species. Anomaiaphis comperei Pergande on Acacia and
Eucalyptus in Australia and none in New Zealand. The original description of Aphis coprosmlJ1