specimen. Flea specimens should be in 10 percent potassium hydroxide (KOH) (1 KOH
pellet per 5 ml water) for at least 24 hours. Punctured I ice specimens should be left in
10 percent KOH for approximately 4 to 6 hours depending on the size of the specimen.
In order to remove the contents of the digestive tract, gentle pressure should be applied
to the abdomen. If the contents are not easiIy removed, it may be necessary to heat the
specimen in the 10% KOH for 1 or 2 minutes untiI the abdominal contents are soft.
c. Transfer the specimen from KOH to distilled water and leave for 20 percent
minutes. Remove the specimen from the water to a solution consisting of 30 to 50
percent alcohol plus 1 percent hydrochloric acid (HCL). Leave the specimen in this
solution for about 20 minutes. Then transfer it to 70 percent, 90 percent, and 100
percent alcohol consecutively, allowing 20 minutes in each concentration.
d. Remove the specimen from 100 percent alcohol to 100 percent cellosolve for
at least one-half hour.
e. Place the flea specimen horizontally in balsam with the head to the right of
the slide and the legs up. If the species of specimen is known before mounting, the
specimens may be mounted in pairs on the same slide, placing the male above the
female. Add a small drop of xylol to the medium and then apply the cover glass. The
slide may be air-dried or placed in a drying oven to harden as described previously.
4-14. MOUNTING MOSQUITO LARVAE AND PUPAE IN BALSAM
a. KiII the specimen in hot water (65 C) or 95 percent alcohol.
NOTE: Minimize the handling of specimens by removing various fluids described from
the specimen container using a pipette or dropper rather than transferring the insects
from container to container.
b. Replace the kiIIing fluid with fresh 95 percent alcohol for 10 minutes. Replace
with a 1:1 mixture of cellosolve and 95 percent alcohol for 10 minutes. Replace with
100 percent cellosolve for 10 minutes to the mount specimen.
c. The abdomen of a culicine larva should be partly severed between abdominal
segments six and seven with a sharp needle.
d. Mount the specimen in balsam with dorsal side up. When mounting culicine
mosquito larvae, the severed terminal segments should be mounted with the left side
up. For all pupae, the cephalothorax is separated from the metanotum and the
abdomen and mounted with the left side up.
MD0170
4-14