87 



Hbmipteba. 



Amongst the hemiptera recorded in C I 

 (1912, pp. 33-40, &c.) as infesfing Cactus plants 

 in this region, are representatives of the destruc- 

 tive genera Narnia and Chelinidea. N. femorata, 

 Stal., whose range extends into Texas, is found in 

 North-Bastern Mexico, where it is reported as 

 attacking the fruit of Opuntias and Cereus. N. 

 inornata Distant, feeds on the joints of Prickly- 

 pear at Durango. Chelinidea tabulata West- 

 wood is found in the same Mexican localities as 

 the last-named. Other plant bugs — e.g., G. vitti- 

 gera, Uhler, Stylopidea picta, Uhler, Sixeonotus 

 luteiceps, Reuter, and Narnia pullidicornis, Stal., 

 are recorded from the Texan frontier. Cory- 

 tlmca decens, Stal., has been taken on Opuntias 

 near Aguas Calientes (C.I., p. 41). 



Another important group of Hemiptera — 

 viz., the Coccidse, which includes the Cochineal 

 insects, is well represented in Mexico on Cae- 

 taceaj. 



The true cochineal Coccus (or Dactylopius) 

 cacti, Linn., is a native of Mexico. On account of 

 its commercial importance in former times a con- 

 siderable amount of literature has accumulated 

 regarding it. A good description of this ancient 

 industry was given by A. Von Humboldt (1811), 

 and many other writers, prominent amongst 

 whom are M. de Russcher, Lopez, and Thierry de 

 Menonville. Many of the accounts have been 

 based on Alzate's treatise published in 1794 in 

 the ' ' Gazeta de Literatura ' ' of Mexico. The bulk 

 of the world's supply was exported previously 

 from Vera Cruz, but the industry is now confined 

 almost entirely to the Canary Islands, though a 

 small quantity is still being raised in Guatemala, 

 Central America (Green, 1912, p. 84). 



Several species of wild cochineal have been 

 found in Mexico as well as in the adjacent por- 

 tions of the United States. Coccus tomentosus, 

 Lamarck*, infests Opuntia fulgida in Northern 

 Mexico (C.I., p. 42), while C. confusus and C. 

 confusus newsteadi, CklL, have also been recorded 

 from North Mexican localities (Cockerell, 1896, 

 pp. 34, 35). Tryon (1910, p. 188), Burkill (1911, 

 p. 304), and Green (1912, p.86), all refer to the 

 introduction by G. A. Prinsep of a wild cochineal 

 (G. indicus, Green) from Mexico into India, via, 

 England. The native home of this lastnamed 

 insect is, however, as yet, not known, unless it be 

 identical with that mentioned in the footnote, t 



* When dealing with Coccus tomentosus Lam. obtained 

 on plants of Opimtia fulgida imported from Arizona into 

 Kew Gardens in 1896, Newstead (1903, p. 225) stated that 

 Mexico was apparently the home of the species, as Curtis 

 and Dug^s had collected specimens of it in that country. 



t The occurrence of a wild cochineal insect in Mexico 

 was announced as early as 1725, its presence in various 

 places in the neighbourhood of Oaxaoa, Yxtala, &c.,bemg 

 incidentally mentioned in accounts of the habits and mode 

 of farming the more precious insect. As an instance, one 

 may cite the following testimony of Matheo de Ognero 

 y Mier, contained in Melohior de Russcher's " Natuerlyke 

 iaistoEie van de Couohenille bewezen met Authentique 

 Documenten " (Amsterdam— H. Uytwerf— 1729) :— 



There is still another kind of cochineal which resembles 

 the^ne but which is named the sylvestre or wild, since, 

 without being an object of care, it provides for itself on 

 other kinds of Nopals which are more spmy and rough. 

 When crushed between the fingers, a reddish coloured fluid 

 escapes from the body. This cochineal has neither the 

 fineness of the other nor is it as abundant ; besides, it has 

 a bad odour and damages the fine cochineal if mixed with 

 it. On account of its being of little value, it is not an 

 object of trade, although it njay be put to other uses. 

 (Translation 9^ pp- 1^2, 133.) 



One member of this Commission has adduced 

 emphatic evidence of a wild cochin,eal insect 

 prevalent in Mexico and destructive to opuntias 

 there. Thus he writes : ' ' Regarding this more 

 vigorous cochineal insect, Thierry de Menonville 

 states: ' They multiply themselves so rapidly as 

 to exhaust and destroy the plants, on which 

 account in Mexico they are abnost all collected at 

 the end of every two months and the plants 

 perfectly cleansed by wiping them with wetted 

 cloths.' " (Giberne, G., 1836.) 



Again, in a report published by the Royal 

 Cadiz Economic Society, it is remarked: " The 

 cultivators of Oaxaca sedulously destroy the 

 sylvestre, saying that it weakens and destroys the 

 Nopals. ' ' 



Thierry de Menonville 's observations were 

 made in Mexico in 1777, but the destructiveness 

 towards prickly-pear plants exhibited is still 

 exercised by them there now. Thus in a work, 

 ' ' Las Plagas de la Agricultura, ' ' published in 

 Mexico in 1902, p. 202, it is stated that " The 

 wild cochineal is a terrible enemy of the Nopal, 

 and can accomplish its destruction, unless steps 

 be taken to prevent its doing so." (Tryon, 1910.) 



A number of parasites of the wild cochineal, 

 G. confusus, are quoted in the list given in the 

 Bulletin on Cactus Insects, as occurring in Mexico 

 (C.I., pp. 46-47). They are Ghilochorus cacti, 

 L., Hyperaspis trifurcata, Schaeffer, Scymnus 

 loewi, Muls., and ;S'. hornii, Gorham, amongst the 

 Coleoptera; and Leucopis hellula, Williston, a 

 dipteron. The last-named, which parasitises Coc- 

 cus confusus in the United States, was reared by 

 Coquillet (1898) from a Mexican coccid Acantho- 

 coccus sp. (C.I., p. 47). Other parasites of the 

 wild cochineal are recorded from localities along 

 the Texan frontier. 



Amongst the less important coceids known 

 to attack Cactacese in Mexico are Pseudoparla- 

 toria parlatorioides, Comstock, and Opuntiaspis 

 pMlococcus, Ckll. (C.I., p. 42), as well as certain 

 species of Diaspis — e.g., D. echinocacti, Bouche 

 (Pernald, 1903), and D. echinocacti opuntim, 

 CklL, the latter variety infesting 0. arborescens 

 and 0. elongata (C.I., p. 42). 



DiPTERA. 



A Ceeidomyiid fly, AsphondyUa opuntice, 

 Felt, which is widely distributed in the southern 

 portion of the United States, extends as far south- 

 ward as San Luis Potosi, in Mexico (C.I., p. 34). 

 This enemy of Prickly-pear, which attacks the 

 fruit causing it to develop into a short joint, is 

 referred to in the report on the investigations in 

 the neighbouring Republic. 



Many Mexican species of Opuntia, growing 

 in the New York Botanical Gardens, were found 

 to be destroyed by another Ceeidomyiid, Itonida 

 opuntice, Felt., whose native home is not yet 

 known. 



A long list of scavengers found in Cacti in 

 Mexico is given in C.I., pp. 47-49. 



ACAEIDA. 



Tetranychus spp. Though not insects, these 

 acarids may be conveniently referred to here. 

 Dr. (Griffiths has given an account (1908, pp. 

 28-30) of a disease caused by a " red spider," 

 Tetranychus opuntice. Banks, the condition 

 being somewhat similar to that produced by 



