76 



C. confustis newsteadi, Coekerell. — This sub- 

 species of tlie cochineal insect was named by 

 Coekerell (1898, p. 675; 1899, p. 284) after Prof. 

 Newstead, who gave a description in which he 

 noted that it differed from G. tomcntosus (1897, 

 p. 75). Newstead 's specimens came from Opww/ja 

 fulgida, from Arizona. Coekerell (1898, p. 675) 

 gives Arizona, Texas, and Mexico as localities, 

 while Green (1912), who gives an account of it 

 (p. 90), adds Colorado. An allied variety, the 

 wild cochineal of Cape Colony, has been named 

 by Green (p. 91) as G. confusus capensis, 

 samples of which were forwarded by the Com- 

 mission from Capetown to Queensland. 



Goccus tomentosus, Lamarck. — This species 

 of wild cochineal resembles the latter in most 

 respects, but instead of each mass of waxy secre- 

 tion covering a number of individuals, each insect 

 of C. tomentosus is separately covered. 



It is recorded from 0. fulgida, from Mexico, 

 New Mexico, and Arizona (C.I., p. 42). Green 

 (1912, p. 87) gives an account of it and mentions 

 the same localities. He regards G cacti, var. 

 opunticB, Coekerell (1896, p. 35) as a synonym, 

 and believes that aU the wild forms — i.e., G. 

 indicus, G. confusus, and sub-species, have been 

 derived from G. tomentosus (Green, p. 80). The 

 relative value of this species and G. confusus as 

 dye-producers has been referred to above. 



The Commission saw species of wild cochineal 

 at Laredo, Brownsville, Alice, Robbstown, and San 

 Antonio (Texas) feeding on 0. lindheimeri and 

 related prickly-pears, while near the last-named 

 town it attacked 0. ferruginispina also. It was 

 seen at Mesilla Park (New Mexico) on 0. cMo- 

 rotica, where it was apparently parasitised by a 

 small moth; at Tucson (Arizona) on 0. arizo- 

 nica, 0. discata, 0. Icevis, and 0. linguiformis, 

 the last-named form being a Texan species in 

 cultivation; at San Diego, Southern California, 

 on 0. occidentalis ; at Wallace (Kansas) on 0. 

 missouriensis ; and on some low-growing undeter- 

 mined species of Opuntia under cultivation at 

 Chico, California. In some of the Texan 

 localities, a ladybird was seen preying on G. 

 confusus. 



Though some joints were found to be very 

 heavily infested, it was rare to find any other re- 

 sult than a more or less well-marked chlorosis. Dr. 

 Griffith's experience is similar, as he informed 

 the Commission that he had never seen a plant 

 appreciably affected by the local species of cochi- 

 neal. Messrs. Hunter, Pratt, and Mitchell, how- 

 ever, have stated (p. 24) that the insect sometimes 

 becomes so abundant as to destroy parts of the 

 plant and occasionally to kill the entire plant, 

 and that much greater injury would be occasioned 

 were the cochineal insect itself not held in checic 

 by various predatory enemies. 



In the neighbourhood of San Diego, South- 

 ern California, a small colony of Goccus confusus 

 was found to be almost completely destroyed by 

 the caterpillar of a moth. 



These wild cochineal insects are evidently 

 controlled to a great extent by various predators 

 and parasites, and therefore the Commission did 

 not see the full destruction that they might cause 

 had these controlling agents been absent. 



White Scale, Diaspis, spp. 



Besides the cochineal, other coccids — viz., 

 certain scale insects (Diaspis, spp.) were met 

 with. A list of those known from the United 

 States is given in C.I., p. 42. It includes Diaspis 

 echinocacti cacti, Comstock, from New Mexico 

 and Arizona, where it occurs on 0. fulgida, 0. 

 arhorescens, and 0. engelmanni; from Texas, on 

 0. lepiocaulis and 0. lindheimeri; while Pernald 

 adds New York and Massachusetts (green-houses) 

 and Iowa. A figure of this species is given in 

 C.I., plate 5. 



Other species are D. echinocacti, Bouche, 

 which Pernald records from Mexico and New 

 York; and D. echinocacti opuntiw, Coekerell, 

 from Texas, on 0. arhorescens and 0. elongata. 



Species of Diaspis were seen by the Com- 

 mission in the St. Louis Botanical Gardens on 0. 

 dillenii, 0. leucotricha, and Nopalea cochineli- 

 fera; at Tucson (Arizona) on 0. fulgida; and at 

 Los Angeles (California) on 0. decumana and 0. 

 monacantha. In no case was any perceptible 

 injury caused.* 



Aphis. 



Dr. Griffiths (1913, p. 20, pi. 7) has recently 

 referred to the proliferation of certain parts of 

 0. puberula caused by the attacks of the "black 

 Opuntia louse," which congregates on the tips 

 of young flower-buds, preventing their opening 

 and rendering them sterile. These infested parts 

 proliferate to give rise to buds which are normal 

 and fertile unless they, too, become attacked and 

 rendered sterile by these insects. A similar result 

 is brought about by the agency of a small 

 cecidomyiid fly, Asphondylia opuntice. 



Various other Hemiptera are named in the 

 list in C.I. (pp. 40-42), Aphis medicaginds, Koch, 

 from Arizona (Texas), being included. They 

 are probably unimportant.t 



The DrPTEROus Enemies. — The Gall Midges. 



Among the Diptera there are certain small 

 insects belonging to the Ceeidomyiidse which 

 injure the prickly-pear. Three of the species 

 belong to the genus Asphondylia and one to 

 Itonida. 



Itonida opuntice, Felt. - 

 This species was first described by Felt 

 (1910, p. 10) as Gecidomyia opunticB, but he has 

 recently transferred it to the genus Itonida. 

 His material came from Dr. N. Britton, Director 

 of the New York Botanical Gardens, who found 

 that it was a very destructive pest of the Opun- 

 tias in the hot-houses. Since the insect had mani- 

 fested itself soon after the receipt of a consign- 

 ment of prickly-pears from Italy, it was suspected 

 that the fly had been introduced from Southern 

 Europe. So troublesome had the pest become 

 that Dr. Britton was obliged to fumigate his col- 

 lection of Cactaees regularly and frequently. 

 At the time of the Commission's visit, the insect 

 had been controlled by him, and a search for 

 the adult as well as an attempt to rear some 

 from plants showing the presence of injuries 

 caused by the larva were unsuccessful. 



* Diaspis is already established in Queensland, but 

 has not as yet proved to be of much value as a cacticide. 



t An aphis has been found in abundance associated 

 with prickly-pear near Goondiwindi in our own State, 

 but it does not do much damage. (Tryon, 1911, p. 17.) 



