60 MISC. PUBLICATION 318, U. 8S. DEPT. OF AGRICULTURE 
PLECOPTERA.—Plecos (plaited), pteron (a wing). 
Four netted, veined wings, front pair narrow, hind pair 
very broad and folding like a fan, folded flat on abdo- 
men when at rest. Mouth parts for chewing. Life 
changes incomplete. Stoneflies. 
MECOPTERA.—Mecos (length), pteron (a wing). Four 
long, rather narrow wings, with numerous cross veins. 
Mouth parts elongated into a snout three times as long as 
width across the eyes; chewing portion of mouth parts at 
end of snout. Life changes complete. Scorpion flies. 
FIGURE 131.—Scor- 
pion fly. 
COLLEMBOLA.—Colla (glue), embolon (a bolt or bar). 
Tiny, primitive, wingless insects. Mouth parts for chewing, 
sunken into head. Never more than six abdominal segments. 
First segment with a forked adhesive organ or ventral tube. 
Fourth segment with a forked spring, which the insect uses 
FicurE 132 — to flip itself along. No metamorphosis, that is, no changes in 
Springtail. form during the life cycle. Springtails. 
STREPSIPTERA.—Strepsis (a turning or twisting), 
pteron (a wing). Four wings, front pair reduced to 
mere clubs, hind pair triangular. Eyes stalked, degen- 
erate. Mouth parts for chewing. Mouth parts mere 
vestiges. Wormlike insects, living throughout life in the 
interior of other insects. (Females without wings, eyes, 
Ficurs 133.—Twisted- or antennae.) Twisted-wing parasites. 
wing parasite. 
CALENDAR OF ACTIVITIES, THIRD YEAR 
Telling others about 
Meetings insaats 
Organization. 
Outline work. 
\Playlets. Surveys. 
Fifth, June 
Sixth, July 
\Demonstrations. 
Seventh, August peat 
Eighth, September \Exhibits. 
Ninth, October 
Tenth, aloveniber 
Eleventh, December 
Twelfth, January }Playlets. 
\Fall surveys. 
PLAYLETS 
Playlets can be effective teaching devices. There is no question that 
through playlets many people can be “shown the light” to better insect 
control when dramatic situations dealing with the solution of some 
