61 



VI. THE UNITED STATES OF AMERICA. 



Introductory. 



The Bureau of Entomology of the United 

 States Department of Agriculture has devoted 

 considerable attention to the study of the insect 

 enemies of cacti, particularly in Southern Texas. 

 Moreover, some investigations regarding the 

 prevalent diseases of prickly-pear in the latter 

 region had been carried out by Mr. F. A. Wolf. 



The Cactaceae of the United States have re- 

 ceived considerable attention from European 

 authors such as De CandoUe, Schumann-, and 

 others, but particularly from local botanists who 

 have studied them in the field, amongst the latter 

 being Bngelmann, Bigelow, Griffiths, Britton, 

 Rose, Coulter, Thornber, Wooten, MacDougall, 

 Cannon, Wolf*, Mackensen, and Toomey. The 

 economic side of the group has been carefully 

 studied by Griffiths (1905-1913), Hare (1906- 

 1911), Thornber (1911), Wooten (1911), and 

 Vinson (1911), especially by the two first named. 

 The chemical side has received much care at the 

 hands of Dr. Hare (1906-1911), while Goss (1895, 

 1903) has also published some data. Mr. Luther 

 Burbank has devoted a great deal of attention to , 

 the raising of varieties of Opuntias with a view 

 to increased succulence and size of joints, and 

 a diminution of their spininess, to make them 

 more valuable as a cattle-fodder. He has also 

 succeeded in improving the fruit production of 

 certain kinds. 



Itinerary. — The Commission arrived in New 

 York on 10th October, 1913. At this city con- 

 siderable assistance was rendered by the Director 

 of the Botanic Gardens, Dr. N. L. Britton, who, 

 in collaboration with Dr. J. N. Eose, of the 

 Carnegie Institute, Washington, is actively 

 engaged in the study of Cactaceaa. Since both of 

 these naturalists had studied this group of plants 

 in various parts of North America and the West 

 Indies, their help and advice were much appre- 

 ciated. 



Visits were then made to the parasitological 

 laboratory of the Bureau of Entomology at 

 Boston, controlled by Dr. A. F. Burgess, and to 

 Albany, where the New York State Entomologist, 

 Mr. E. P. Felt, was consulted, this investigator 

 being an authority on a group of insects, some 

 members of which are known to be serious para^ 

 sites of prickly pear. • 



At Washington, D.C., the Commission re- 

 ceived every assistance from Hon. H. F. Houston, 

 Secretary for Agriculture; from Dr. L. 0. 

 Howard, Chief of the Bureau of Entomology, 

 and his assistants, particularly Messrs. W. D. 

 Hunter and W. D. Pierce; from Dr. Taylor, 

 Chief of the Bureau of Plant Industry, and Dr. 

 D. Griffiths, Dr. W. A. Orton, and Miss E. C. 

 Field, members of his scientific staff; Dr. 

 Merriam (former Chief), Messrs. H. W. Hanshaw 

 (Chief) and V. Bailey, of the Bureau of 

 Biological Survey; and from Dr. Dyar and 

 Messrs. F. Knab, E. A. Schwarz, A. Busck, 0. 

 Heidemann, and A. CaudeU, of the entomological 

 staif of the National Museum. Some of these 



* Wolf (1912 a, 1912 b) has given some account of 

 the anatomy of one of the prickly-pears, O. Undheimeri. 

 Solereder many years ago published a good deal of infor- 

 mation regarding them, and in his work quotes from the 

 labours of many other botanists regarding this group of 

 plants. Quite recently in our own State, Dr. Shirley and 

 Mr. Lambert (1914) have examined anatomically some of 

 the species naturalised in Queensland. 



men, notably Dr. Griffiths, Mr. Hunter, and Mr. 

 Pierce, have had considerable experience with 

 certain phases of Prickly-pear questions, their 

 work being referred to later in this report. 



In order that the Commission might utilise 

 its time to the best advantage. Dr. Griffiths kiudly 

 outlined an itinerary which was in the main 

 followed, the only modifications being those sug- 

 gested by Dr. Howard, and those which were 

 found to be advisable during the journey. Dr. 

 Howard very generously placed at the disposal 

 of the Commission, during its work in Texas, the 

 services of one of his officers, Mr. J. D. Mitchell, 

 who has had a very long experience of prickly- 

 pears in the field, and who, in conjunction with 

 Messrs. Hunter and Pratt, is the author of a 

 paper on " The Principal Cactus Insects of the 

 United States." His assistance is gratefully 

 acknowledged. 



The journey to Texas was made via St. Louis. 

 Here Dr. Rose was interviewed, and a visit was 

 paid to the " Shaw " Botanical Gardens, where 

 Dr. S. T. Moore, the Director, and Dr. J. M. 

 Greenman, keeper of the herbarium, were con- 

 sulted. Dr. Engelmann's types of Opuntias are 

 located in this iastitution. 



The itinerary in Texas included the follow- 

 ing districts: — Dallas, San Antonio, Laredo, 

 Alice, Robbstown, Brownsville, and Sinton. 



At Dallas, a visit was paid to the Entomolo- 

 gical Experiment Station, under Mr. F. C. 

 Bishopp, where the greater part of Messrs. 

 Hunter, Pratt, and Mitchell's work on cactus 

 insects was carried out. Mr. W. Sinclair's farm 

 near San Antonio was iuspeeted, since it was at 

 this place that Dr. Griffiths carried out much of 

 his experimental work regarding the feeding of 

 cactus to dairy cattle. Mr. B. Mackensen 's col- 

 lection of Opuntias was also examined during our 

 stay in San Antonio. It was at this city that Dr. 

 F. Chittenden, of the Bureau of Entomology, 

 was interviewed. While at Brownsville, the 

 assistance of Mr. M. Vickery, Entomologist at 

 the Plant Introduction Garden of the Bureau of 

 Plant Industry, was sought. It is here that Dr. 

 Griffiths has one of his large experimental cactus 

 plantations. 



In addition to visiting the abovenamed in- 

 dividuals and institutions, the Commission exam- 

 ined the CactaccEe in the surrounding country as 

 far as circumstances allowed. 



From Texas the journey was made west- 

 ward to Mesilla Park in New Mexico, where Pro- 

 fessors R. F. Hare, D. E. Merrill, and H. S. 

 Hammond were interviewed. Dr. Hare has de- 

 voted considerable attention to the chemistry of 

 the prickly-pears, and in conjimction with Dr. 

 Griffiths has published much information, while 

 Mr. Merrill has given some notice to the insect 

 fauna of local Opuntias. 



At Tucson in Arizona, very willing assistance 

 was given by Professor J. J. Thornber, of the 

 University of Arizona, who is interested not only 

 in the purely botanical side, but also in the 

 matter of using Opuntias as a stock-fodder. The 

 published work of himself and his colleague, Dr. 

 A. E. Vinson, is referred to later. A visit was 

 paid to the Carnegie Institute's Desert Labora- 

 tory, near Tucson, where Dr. D. T. MacDougall, 

 its Director, Dr. Cannon, and others are carrying 



