38 THE BLOWFLIES oF NortH AMERICA 
tween the thumb and forefinger of the left hand with the head 
of the fly toward the palm of the hand and the legs upward. The 
hands are then placed on the microscope stage, backs down, 
with the middle fingers placed firmly together. The dissecting 
needle is held like a pencil in the right hand (see Fig. II). This 
method assures steadiness and a minimum of damage to’‘speci- 
mens. Middle or high magnification ‘is ‘desirable. Dissecting 
needles most suitable for this work are made by forcing a slight- 
ly hooked minuten nadeln or No. 00 steel insect pin into a suitable 
handle. Sealing wax will usually hold the pin in place per- 
manently. 
The needle is gently thrust between the genitalia and the edge 
of the fifth sternite. The hook is then slightly turned toward 
Fig. II. Method of holding specimen and position of hands during dissec- 
tion of the genital segments of the male. 
the genital capsule and carefully retracted in an attempt to 
break the muscle attachments between the genitalia and the 
terminal portions of the abdomen. This action should be per- 
formed several times on each side until the entire genitalia ap- 
pear loose but still remain intact with the tip of the abdomen. 
The needle is next hooked to the tips of the inner forceps and by 
gentle retraction the parts are rolled outward into view. If com- 
plete dissection is necessary, attachments are finally severed 
with the needle. If not, the dissection is complete as soon as the 
parts are fully exposed. 
The genitalia to be fully dissected are placed in a small ecru- 
cible containing 10 percent potassium hydroxide and carefully 
brought almost to the boiling point. A quick inspection under 
the binocular microscope will show the progress of clearing. The 
clearing should not be carried too far, for certain internal fea- 
