August, ’24] 
HAMLIN: PRICKLY-PEAR CONTROL 
453 
to free it from all other insects. The crawlers then leave the cloth and 
settle upon the cactus, starting a culture free from enemies. The edges 
of doors to cochineal cages must be kept sealed with paper to prevent the 
entry of any of its many natural enemies. 
The volume of insects constantly handled in the insectary was 
necessarily greatly beyond the requirements of the next consignment. 
In the first place, several cages of each species were necessary to insure 
a sufficiency of material in the event that certain cages should become 
contaminated with natural enemies. Again, since shipments could be 
forwarded on only one steamer departing at stated intervals, a number of 
cages of each species in several different stages of development were 
essential in order to have available the most favorable stage for ship¬ 
ment at the time the consignment was to be forwarded. 
In several instances field-collected material was shipped to Australia. 
This was due, in part, to our inability to give sufficient detailed study to 
exceptional species while caring for the large stocks above mentioned. 
Again, such sendings were sometime made to meet the exigencies of the 
situation as regarded the needs in Australia and the possible termination 
of the North American work. 
The North American force had neither the time nor equipment re¬ 
quired to prepare pure cultures of the disease-producing organisms. 
Consequently, the writer found it necessary to send infected cactus 
segments or to rely upon the courtesy of several phytopathologists to 
supply pure cultures for us. 
Shipment of Cactus Insects 
The great bulk of insects was shipped in the large cases, while small 
numbers of certain species were sent in the small mailing cases. The 
latter were, of course, handled as parcel post, there being limited ventila¬ 
tion, no sunlight, and abnormal temperatures. 
At the outset the shipping cases were placed partly on deck under 
outside conditions and partly in that chill-room most remote from the 
refrigerating machine. The unfavorable results secured from the chill- 
room portions of the first few shipments sufficed to eliminate that method 
of shipping. 
The packing of various insect species was greatly influenced by their 
observed tendencies in the field and by the experience gained from rear¬ 
ing them in the insectary. These previous phases of work enabled 
decisions as to the method of packing the cactus, kind of cactus suit¬ 
able, stage of insect best adapted to shipment, and number of indi- 
