70 



O. (Philopuntia) clathratus, Le Conte. — In 

 1903 Prof. Townsend referred to the finding of 

 this species in abundance in Southern Texas, 

 breeding in the ends of joints of 0. leptocaulis. 

 The larva eats out the tissues, killing the part 

 affected, and then forms a cell in which it 

 pupates. Its range is given (C.I., p. 30) as 

 Colorado to Brownsville (Texas) and Arizona. 

 Mr. Pierce (1911, p. 165) stated that a clump- 

 ing of the branches takes place if the infesta- 

 tion be heavy. Though the " witch's broom " 

 condition of 0. leptocaulis was seen by the Com- 

 mission near San Antonio (Texas), the weevil 

 was not found. 



Other species of Gerstffickeria mentioned in 

 the list given in the Bulletin on Cactus Insects 

 (pp. 43-44) or in Mr. Pierce's paper (1911), as 

 occurring in U.S.A., are G. Mfasciata, Gerstsec- 

 ker, reared from larvse infesting Echinocactus 

 setispinus (San Antonio, Texas) ; G. basalts, Le 

 Conte, from Colorado and Nebraska; G. tur- 

 hida, Le Conte, and G. alternata, Pierce, from 

 Arizona; G. opuntim, Pierce, and G. cadophaga, 

 Pierce, from Southern Texas ; G. fasciata, Pierce, 

 from Florida; G. tessellata, Pierce, from Colo- 

 rado; G. profusa, Casey, from Texas, and G. 

 dilitata, Casey (probably a variety of G. hub- 

 lardi), from Florida. 



The Black Cactus Weevils, Cactophagus, spp. 



These are large black weevils allied to Calan- 

 dra and Sphenophorus. Dr. C. Riley (1888, p. 

 199), in his article on the "Food Habits of 

 North American Calandrinfe," stated that, as 

 far as known, C- vaUdus was restricted to 

 Opuntias. 



The Commission found beetle larvas, eorre- 

 s]>onding in size and appearance to those of a 

 large Sphenophorid, feeding in the roots of the 

 common low-growing prickly-pear (0. missou- 

 riensis), near Wallace, in Western Kansas. In 

 one instance the plant had almost succumbed to 

 its attacks. 



Mr. F. Blaisdell, a Californian entomologist, 

 was understood to say that he had found G. vali- 

 dus in great abundance around the bases of 

 prickly-pear near San Diego in Southern Cali- 

 fornia. A visit to the locality failed to reveal 

 the presence of this or any other weevil associ- 

 ated with Opuntias there (November, 1913). 



Cactophagus spinolm, Gyll. (syn. G. vaUdus, 

 he Conte) has been recorded from California 

 end Arizona. C. hiibbardi, Schwarz, which forms 

 tunnels in the giant cactus Carnegiea gigantea, 

 in Arizona (Hubbard, 1899; Schwarz, 1899), is 

 capable of living for at least four years, accord- 

 ing to observations recorded by Schwarz (1901, 

 p. 368; p. 431). 



T. L. Casey published in 1892 a systematic 

 arrangement of the genus Cactophagus. 



Sphenophorus acupunctatus, Gyll., was 

 stated by some local entomologists to have been 

 foiind associated with priekly-pear in the region 

 between San Bernardino (Southern California) 

 and Arizona, but Mr. Blaisdell said that both 

 this species and its allj^, 8, yuccw, liorn, were 

 associated exclusively with Yucca plants. Speci- 

 mens were not found by the Commission during 

 its shm Visit to the, San Dlege clistriet. 



Even if these Sphenophorids were cactiis 

 destroyers, their introduction into Australia 

 would be unwise, as one species of the group 

 feeds indifferently on palms, bananas, and 

 sugar-cane, and another on the two last- 

 named plants. Some, however, appear to be 

 restricted in their dietary to one plant— e.g., 

 those infesting Yucca spp. 



Other beetles. 

 Other beetles which have been mentioned 

 (C.I., pp. 42-44) as enemies of cacti are the 

 following : — 



Onychobarius mysticus, Casey, on 0. lepto- 

 caulis in Texas, Arizona, and New Mexico, and on 

 0. fulgida in Arizona. 



Trichochrous texanus, Le Conte, sometimes 



injures the flowers of Opuntias in New Mexico 



and Texas to such an extent that fruiting is 



jprevented, but it is probably not confined to the 



Cactacese for its food (C.I., p. 32). 



The Lepidopteeous Enemies. 



Amongst the moths which feed on prickly- 

 pears, there are some which are very serious 

 enemies — ^viz., Mimorista and the various species 

 of Melitara. 



Mimorista flavidissimalis, Grote. 



This small yellowish or straw-coloured 

 Pyralid moth is briefly described, and an illus- 

 tration of its work given, in the Bulletin on 

 Cactus Insects (p. 21, plate 3). From one to 

 seven eggs are placed by the female moth on the 

 upper edge of the stem-joint. On hatching, the 

 minute grubs make tiny holes through the skin 

 of young segments of the host-plant, and so 

 bore their way into the interior. The cater- 

 pillar is a smooth, glossy, yellowish-white insect 

 which when fully grown measures about 11 mm. 

 There are a few long white hairs occurring 

 sparsely on the anterior segments especially. The 

 head and cervical shield are yellow, the latter 

 bearing two very small black spots. When full- 

 fed, the larva emerges from the joint and forms 

 a cocoon resembling paper, within which it 

 transforms into a shiny, light-brown chrysalis 

 about 9 mm. long. 



The site of this injury is marked by an 

 exudation of the cell-sap, which, becoming mixed 

 with silky threads and excreta from the insect, 

 forms a protecting cover beneath which further 

 damage is executed. In cases where the wounds 

 have healed, this foreign matter persists on the 

 injured areas as dry brown or grey flakes. If 

 only a few larvte be present, the injury caused by 

 them is likely to heal, a deformed segment being 

 the result. If, however, several larvse attack, 

 then the death of the joint is usually the result, 

 as decay sets in and the part blackens, dries, 

 and falls. Their importance in checking the 

 growth of prickly-pear depends upon the fact 

 that they will attack the youngest shoots as well 

 as those which are rather older. 



Since there are several broods in a season, 

 this moth is a serious enemy to Opuntias. Mr. 

 Mitchell has estimated that from 50 to 75 per 

 cent, of all new growth is destroyed through its 

 agellcy over considerable areas in Southern 

 TeXM. it 19 stated that In the restricted regioo 



