1940] 
Early Stages of Lepiselaga crassipes 
9 
River between Gamboa and Madden Dam in the Panama 
Canal Zone, I occasionally dipped up small pupal shells of 
what I suspected might be Lepiselaga. Comparison of these 
with a specimen in our collection from which Dunn had bred 
Lepiselaga confirmed my suspicion. 
Although, for reasons which are not known, Pistia has 
become very scarce throughout the Canal Zone this year, I 
have taken the adult Lepiselaga in fair numbers throughout 
the year. I suspect, therefore, that it is not entirely de- 
pendent on this plant, but may be associated with other 
types of aquatic vegetation as well. In April 1939, while 
collecting in a small slough near the laboratory's station at 
Juan Mina on the Chagres River, I secured two small green- 
ish larvae from the matted floating vegetation near the shore 
line. This vegetation consisted of floating debris, mats of 
filamentous algae, the water-fern Salvinia , and a few small 
plants of Pistia not over 1.5 inches in diameter. The larvae 
were associated with a rather rich fauna of aquatic insects, 
including larvae of Odonata, Ephemerida and Stratio- 
myiidx, and numerous species of aquatic Coleoptera and 
Hemiptera. At the same time I also took two pupal shells. 
Later, in mid-May of the same year, I collected two more 
larvae of Lepiselaga in a grassy swamp near Gamboa. They 
were in the floating scum on the water, and no Pistia was 
present in the swamp. 
The first two larvae were kept in the laboratory in shell 
vials measuring 3x1 inches, into which about 1 inch of 2% 
agar had been poured. This medium remains more or less 
transparent for one or two weeks, when the larvae may be 
removed to a new tube if it is desired to keep them under 
close observation. Inoculation of the medium with some 
unicellular green alga seems to keep the medium from be- 
coming putrid for a longer time, but the dark green color 
interferes with observation. To provide a suitable place for 
pupation, paper towelling is cut into strips 1.5 inches wide 
and 3 or 4 inches long, rolled into a cylinder the size of a 
lead pencil, moistened and inserted upright into the agar. 
The tubes are stoppered tightly with cotton, which must not 
touch the roll of paper, or it will suck all excess moisture 
from the paper and agar. The larvae may be fed upon 
aquatic earthworms, Chironomid larvae or other small soft- 
