16 UNITED STATES NATIONAL MUSEUM BULLETIN 276 



arrangement, when jars of water are changed, it is possible for larvae 

 from one cage to get into the cage below or above, but the chance of 

 this happening is practically nonexistent if any larvae near the opening 

 are moved away and the fresh jar of water is screwed into the ring as 

 soon as the old one is removed. Usually it is not necessary to do this, 

 since water can be added by pouring it into the jar from the cage above. 



After the larvae had spun up, the cocoons were removed from the 

 cages and placed individually in small paper drinking cups which were 

 covered with a polyethylene square held in place by a rubber band. 

 The cups were placed in cardboard trays and examined each night. The 

 use of individual emergence cups accomplished two things : it separated 

 males from females for use in breeding experiments, and it prevented 

 active moths from disturbing newly emerged ones or inactive ones, 

 thereby resulting in better specimens. 



In addition to the insectary-trailer, the other major piece of equip- 

 ment was a pickup truck with a camper attached. The insectary-trailer 

 was parked in a central location in the area being studied, and the 

 pickup-camper was used to make collecting trips of from 1 to 4 days 

 into the surrounding territory. The pickup-camper was ideal for this 

 kind of field work since it was possible to stop overnight just about any 

 place without wasting time pitching a tent or looking for a room. 



Larvae collected in the field were held in large .004-polyethylene bags 

 until they could be transferred to cages in the insectary-trailer or pre- 

 served. This was very satisfactory, and healthy larvae showed no ill 

 effects when held in bags as long as a week, provided they were not left 

 in the sun. If left in the sun both the temperature and the condensation 

 of moisture on the inside of the bags became excessively high. 



Field Collecting 



The number of larvae collected, preserved, reared, etc., varied 

 considerably from collection to collection. Only 45 cages were avail- 

 able for rearing, so it was not possible to rear all collections, nor 

 was it necessary, since some collections were similar to others. In 

 addition to the collections which were made, numerous other colonies 

 were examined in the intervening areas, and notes were taken on them. 

 Whenever possible, each collection consisted of the larvae believed 

 to have hatched from a single egg mass, but, as will be pointed out, 

 it is virtually impossible to be absolutely certain that all larvae in 

 a tent hatched from a single egg mass unless the egg mass is collected 

 and hatched. 



