8 



254 Phylum Arthropoda 



molted from nymphs may be stored a year or more without excessive 

 mortality by placing them in pyrex cylinders or "longevity tubes." These 

 tubes are 8" in length by i%" in diameter. One end is plugged with well 

 packed earth or with Plaster of Paris for a distance of 2", and a few 



coarse wood shavings or dried leaves are added 

 so that the ticks are not forced into direct 

 contact with the plug (Fig. 56). From 300 

 to 400 ticks are placed in the tube and the 

 latter is closed by a piece of muslin tied over 

 the open end. The tubes are placed upright 

 inside 4" galvanized metal cylinders set in the 

 ground to their full length. The plugged end 

 of the pyrex cylinder must be in close contact 

 with moist soil. Moisture is supplied to the 

 surrounding soil as necessary. The ticks are 

 thus free to seek favorable humidity conditions. 

 The "tick yard" in which the tubes are placed 

 must be constructed or located so that the 

 direct sun rays will not fall on the tubes. 

 During the winter the tubes may either be left 

 in the ground or stored indoors at 6° C. The 

 ticks will survive outdoor conditions unless 

 subjected to unusually abrupt transitions of 

 temperature, particularly from cold to heat. 



For periods of at least 6 months adult ticks 

 may be stored in pill boxes at 6° C. with the 

 relative humidity maintained at about 80%. 



Engorged female ticks may be stored to delay 

 oviposition for periods up to 4 months in card- 

 board pill boxes at temperature and humidity 

 conditions as stated above. 



Immature Stages. Unfed larvae may be 

 stored for periods up to 2 months under the 

 conditions just stated. 



Unfed nymphs may be kept successfully for 

 periods up to 6 months in longevity tubes in the 

 tick yard in the manner described for adult 

 ticks. However, equally satisfactory results will ordinarily be obtained 

 by storing the tubes upright on a tray of moist sand in a thermal cabinet 

 operated at 6° C. 



Fed larvae and fed nymphs are susceptible to desiccation at the lower 

 ranges of humidity and to molds at the higher ranges. Therefore, it is 

 more desirable to store immature ticks as unfed nymphs. 



* \% » 



Fig. 56. — Diagram of 

 pyrex "longevity tube," 

 used for storing unfed 

 adult or nymphal ticks 

 for long periods. 



