THe BroLtocy or EpHypRA SUBOPACA LOEW 567 
LIFE HISTORY 
THE LARVA 
Morphology 
Various methods were tried for studying the anatomy of the larva. 
The following methods yielded the most satisfactory results. 
_ For the muscular system, it was found that specimens were best fixed 
in slightly warm Bouin’s or Gilson’s solution. Both the cutaneous and 
the cephalopharyngeal musculatures appeared opaque white, and were 
thus to be distinguished from other structures. For the nervous, alimen- 
tary, tracheal, and vascular systems and the imaginal disks, 10-per-cent 
formalin seemed best. The fine branches of the nerves and tracheae were 
preserved intact and were recognized and distinguished from one another 
under a binocular microscope with the aid of bright sunlight or the arti- 
ficial light of a nitrogen-filled lamp. The imaginal disks were best studied 
by staining with diluted methylene blue (5 drops to 5 cubie centimeters 
of water); this distinguished them from the nervous ganglions, which do 
not take the stain to the same degree. The dorsal vessel, the ring, and 
the entire alimentary system were preserved in perfect condition in this 
weak fluid. In checking up the gross dissections, serial sections were 
cut from 5 to 10% with a microtome. Here again Bouin’s and Gilson’s 
solutions were the fixers used. The following was the procedure: 
Certain parts not to be studied were snipped off in order that the fixer 
might penetrate quickly. The specimen was killed in hot solution and 
fixed for from 12 to 24 hours, washed in 85-per-cent alcohol which was 
changed three or four times a day, and stained in toto in borax carmine 
for from 24 to 48 hours. The specimen was then de-stained in 70-per- 
cent acidulated alcohol for from 12 to 24 hours, in 85-per-cent alcohol for 
24 hours, in 95-per-cent alcohol for 24 hours, in absolute alcohol and 
cedar oil for 24 hours, in cedar oil for 24 hours, in 56° paraffin for 24 hours; 
ection from 5 to 10%; xylene 5 minutes; in 95-per-cent alcohol 5 minutes; 
in carbol-xylene for 5 minutes. Lastly, the specimen was mounted in 
alsam. 
External structures 
General features— The body of the larva consists of twelve segments. 
he first, or head, segment is often retracted and not visible from 
