346 Phylum Arthropoda 



are easily observed due to their wilting. Clip these twigs to a length 

 of 3 to 4 inches, stripping off the leaves to prevent overheating when 

 put in bags for convenient carrying. Upon completion of collections 

 and arrival at the laboratory, the twigs are spread on pans of i%-inch 

 green apples so that larvae emerging from the drying twigs may have 

 sufficient food for normal development. Pans used are galvanized re- 

 frigerator pans, 15 inches in diameter, placed in an incubator regulated 

 for 8o° F. and 50% relative humidity. Twigs are removed after three 

 days and corrugated paper strips, % mcn m width, are fastened around 

 the pan tops by means of metal strips doubled to form a V, one end 

 being longer and bent over the pan lip to hold it in place. Unbleached 

 muslin covers are tied over the pans to prevent mature larvae from 

 crawling away, as not all find openings in the strips. As soon as the 

 larvae begin spinning, the corrugated strips are removed every other day 

 or, at times, daily, and new strips substituted. Strips containing the 

 spun larvae are treated in two ways. Those for immediate emergence 

 are placed in refrigerator pans, covered with muslin and kept in the 

 emergence cage. The others are clipped into jelly jars and held at a 

 temperature below 45' F. 



An emergence cage may be constructed by making a framework of 

 two by fours with a door hung at one side. Shelves are built along the 

 side to hold the refrigerator pans and a bench for working. The frame 

 is enclosed with black cambric except for one end (covered with white 

 cheesecloth), which faces the room windows. A temperature of 75 ° 

 to 8o° F. and a humidity of about 50% is maintained by means of air 

 conditioning apparatus. After about 6 days from date of spinning moth 

 emergence starts and the pans are left open, allowing the moths to fly 

 directly to the white screen. Covering the pans is an emergency measure, 

 as parasites attacking the moths in the prepupal stage may become 

 numerous. 



The moths, being phototropic, are easily collected from the white 

 screen by means of a suction apparatus. An ordinary hand hair dryer 

 with the heating unit removed is used for creating a suction sufficient 

 to draw the moths from the screen into the prepared containers. The 

 containers used are ordinary pint Fonda cartons with a i-inch hole cut 

 in the bottom and stopped up by a cork covered with cheesecloth. The 

 top is partly cut away, leaving just the outer ring and a narrow section to 

 help stiffen the cover on its being replaced. A section of cheesecloth 

 placed over the carton and the cover forced back in place makes a tight 

 container with plenty of ventilation. The cheesecloth may be dampened 

 to aid in preserving the confined moths. A ring of cardboard slightly 

 larger than the pint containers mentioned is fastened to the side of the 

 hair dryer where the air is sucked in. Elastic bands with clips attached 



