State would bear whatever expense was necessary. The Bureau of Entomology 

 offered to supervise and be responsible for the work, which would be placed under 

 the control of an officer who had had experience in the field, and was familiar 

 with cactus insects and with parasitological work. Assistance would be required 

 for him, hence the suggestion that a trained entomologist belonging to the 

 Dallas Experiment Station of the Bureau might be seconded for this purpose. 

 About £40 per month would be required to pay salary and expenses. 



Mr. F. W. Maskew, the Chief Inspector of the Board of Horticultural 

 Commissioners, San Francisco, who is also an officer of the Bureau of Ento- 

 mology, offered to attend to the transmission to Australia of any parcels of 

 cactus insects which might be forwarded to him by the officers of the Bureau. 



Professor J. J. Thornber, of Tucson, Arizona, and Professor D. E. Merrill, 

 of MesUla Park, New Mexico, also expressed their willingness to co-operate 

 with the Bureau of Entomology in any way desired. 



Dr. C. Spegazzini, La Plata, Argentina, informed the Commission that 

 he waS' willing to assist in regard to any insects which it was desired to obtain 

 from that country. 



We desire to emphasise the necessity for such provision, already alluded 

 to, being made in Queensland in good time, so that any insects whose introduction 

 is authorised by the Government, may, on arrival, at once receive the proper 

 care and attention needed for their propagation and for their serviceable 

 employment. 



The Policy of Introducing Insects. 



On the general policy of introducing living insects at all when regard 

 is had to the fact that so many imported ones are already highly destructive 

 to vegetation, the Commission may make a short pronouncement. 



It may be affirmed with regard to the Cactus insects that in some respects 

 they are as peculiar as are the Cactacese themselves, and that hence the associa- 

 tion is often very close between plant and insect. This statement, however, is 

 not of general application, but it is obviously true as regards certain kinds. It 

 especially applies to the true Cochineal Insects — Coccus cacti and its congeners. 

 So close indeed is it that not only are these insects incapable of living on plants 

 outside the Cactaceous Order, but they will often live only on particular species 

 of prickly-pear. Thus of the two Opuntias named, cochinelifera to indicate 

 the association referred to, the Precious Cochineal insect {Coccus cacti) will 

 subsist on that so designated by Miller, whereas it will not attach itself to that 

 named cochinelifera by Linna?.us (our Nopalea cochinelifera). Similarly the 

 Cochineal of the latter, Cocctis confusus Newsteadi is confined to it. So again 

 another wild Cochineal Insect is restricted as far as we know to Opuntia mona- 

 cantha. This statement as regards the cochineal insects is based on recorded 

 observations and experiences of upwards of a hundred years standing and 

 extendmg to many different countries. The last remark cannot be made respec- 

 tmg certam other prickly-pear loving insects, but these, too, from other con- 

 siderations, however, we conclude are restricted to cacti. 



With regard to other prickly-pear insects mentioned in this Report, we 

 can pronounce on their exclusive cactus relationship almost with equal confidence. 

 Not only have they and their habits formed the bases of special memoirs implying 

 diverse and extended observation, but the special insect-groups in which the? 

 are embraced have received the exclusive attention of entomologists of the highest 

 repute hvmg m the country where they occur : moreover, they are included 

 m the comprehensive lists detailing all the food habits of insects amassed by the 

 Division of Entomology of the United States. From the sources thus indicated 

 has been denved our knowledge-confirmed as it has been by our own observa- 

 tions—on which this conclusion is based. 



