86 



VII. MEXICO AND CENTRAL AMERICA. 



Owing to the unsettled state of Mexico, 

 particularly the prickly-pear regions, the British 

 Ambassador at "Washington, D.C., and the 

 Officials of the Department of Agriculture at 

 Washington, as well as those along the Texan 

 border, strongly deprecated any attempt on the 

 part of the Commission to enter that country. 

 As the Mexican Highlands, especially the north- 

 ern portion of it, possess a particularly rich 

 Cactus Flora, it is to be regretted that oppor- 

 tunity did not allow of systematic search and 

 inquiry being made there. The Commission had 

 to content itself with a few visits to certain 

 northern towns just within the Mexican frontier. 



The following report is mainly a compila- 

 tion of information gained from various sources 

 during the course of inquiry in the United States 

 of America. 



Since more species of Prickly-pears occur 

 indigenously in Mexico than in any other part 

 of America, the Index Kewensis enumerating 

 upwards of fifty nominally described endemic 

 species, the literature referring to Mexican 

 and Central American Opuntias is very exten- 

 sive. Earlier work, based largely on specimens 

 cultivated in European gardens, is included in 

 Schumann's Monograph (1899-1903). Since then 

 Dr. Griffiths (1908-1912) and Dr. Rose (1890- 

 1913) have been working steadily at the sys- 

 tematic side of the group. 



Some of the Mexican species have become 

 naturalised in Australia, e.g. : — 



(1) 0. foment osa, the tree pear of Heli- 

 don, Rockhampton, Gayndah, and 

 other districts in Queensland; 



(2) The "Red Mexican" or "Westwood 

 Pear"; and 



(3) The "Yellow Mexican" species, both 

 found in the Rockhampton district; 



(4) 0. microdasys, which Mr. Maiden has 

 stated is now to be found in the Pil- 

 laga Scrub (N.S.W.) ; 



(5) 0. imhricata, which occurs in scat- 

 tered situations in New South Wales 

 and in one locality in Queensland ; 



(6) Nopalea cocMnelifera, which is found 

 at Gayndah and Emerald, is probably 

 a native of Mexico. 



DESTRUCTION BY FUNGOID 



DISEASES. 

 Dr. Griffiths (1908, p. 28) gave a short 

 account of the "shot-hole" disease, whose range 

 is stated to be from Texas to Mexico City, and 

 whose causal agent was identified as Perisporium 

 Wrightii. As pointed out by Wolf (1912) the 

 parasite is GlcROsporium lunatum, P. Wrightii 

 being a comparatively harmless enemy of the 

 Prickly-pear in those regions. This "shot hole" 

 is referred to at some length in the report on the 

 investigations in the United States. Perisporium 

 Wrightii also occurs in Northern Mexico. 



DESTRUCTION BY RODENTS. 



The range of several of the rodents, such as 

 Neotoma spp. and others, whose activity in 

 attacking and even destroying Prickly-pear in 

 Texas, New Mexico, and Arizona, has been men- 

 tioned in the report on the Commission's work 

 W tlje United States, extends into Mexico. As 



already stated in that section of the report, these 

 animals are general feeders, whose introduction 

 could not with safety be recommended (see 

 Bailey, 1905). 



INSECT ENEMIES. 

 Since most of the insects mentioned below, 

 or else species allied to them, have been referred 

 to in the report on the investigations in the 

 United States, there is not any need to dwell 

 on them again. The geographical range of 

 many of them extends from Texas, Arizona, and 

 New Mexico into the Republic of Mexico. Besides 

 these there are others not represented in the 

 United States, though related species may occur 

 there. Many are recorded in the Bulletin on 

 Cactus Insects (C.I., 1912) from localities on 

 the Northern bank of the Rio Grande, e.g., 

 Brownsville, Laredo, Eagle Pass, and El Paso,' 

 the range of at least some of them, no doubt, 

 extending across that river into Mexico. The 

 effects produced by the various insect enemies 

 have been described earlier in the report. 



COLEOPTEEA. 



Amongst the cactus beetles belonging to the 

 genus Moneilema are certain Mexican species, 

 M. variolare, Thomson (Duges, 1886), and M. 

 Icemthorax, White (Duges, 1901). Horn (1885) 

 has recorded the following as occurring in Lower 

 California: — M. semipunctatum ; M. suhrugosum 

 Blanch. ; M. spoliatum Horn. 



Cactophagus spinolm, Gyllenhal (syn. C. 

 ■validus Le Conte), is recorded by Duges (1886), 

 Champion (1910), Tryon (1911, p. 19), and 

 Messrs. Hunter, Pratt, and Mitchell (p. 44), as 

 infesting certain Mexican species of Opuntia. 

 Champion (1910, p. 84) mentions that Cacto- 

 phagus striata foratus, Gyllenhal, attacks Cereus 

 in Costa Rica. 



The Cactus weevils have received attention 

 lately from Mr. W. D. Pierce (1912), in whose 

 paper several Mexican and Central American 

 species are referred to. They belong to the 

 genus GcrstcEckeria, which has been subdivided 

 by him into a number of subgenera. They are G. 

 (Xenosomina) inflata, Champion, from Guate- 

 mala; G. (Xen.) turpis, Champion, also from 

 Guatemala; G. {Gcrstceckeria) iifasciata, Ger- 

 stascker, from Mexico ; G. (PMlopuntia) leseleuci, 

 Champion, from various Mexican localities; G. 

 (Philop.) lacti, Champion, from Southern 

 Mexico; G. {Philop.) cruciata, Champion, from 

 N.E. Mexico; as well as G. (Phil.) curvilineata. 

 Champion; G. (Phil.) tolucana, Champion; and 

 G. (Phil.) lineatocollis. Champion, from various 

 localities in Mexico. Besides these there are 

 many species from the Mexican border of Texas, 

 e.g., G. clathrata, Le Conte, G. cactophaga, Pierce, 

 and G. nohilis, Le Conte. 



Lepidoptera. 

 No serious Lepidopterous parasites of 

 Prickly-pear are quoted in the Bulletin on Cactus 

 Insects as occ^^rring in Mexico. Since certain 

 species of Melitara are to be found in Arizona, - 

 New Mexico, and Texas near the Mexican frontier, 

 it is not unlikely that the range of some of them 

 extends into Northern Mexico. One, M. para- 

 bates Dyar, has beeii reporded from tlte Republic, 



