100 



The following description of 0. inermis, D.C., 

 is based on field notes made while examining 

 specimens of the plant growing at Colonna and 

 Ceja Negro, Pinar del Rio, respectively. Gen- 

 eral colour rather dark dull green. Stem-joints 

 oval but somewhat obliquely narrowed towards 

 the base ; measurements of terminal segments, 16 

 cm. X 8 cm., 16 cm. x 7 cm., 15-5 em. x 8 cm., 12-5 

 cm. X 12 cm. Intermediate joints larger, 23 e. 

 X 9 cm. to 30 cm. x 9 cm. Areoles, 4 to 5 in an 

 oblique row. Leaves about 4 mm. long, small, 

 conical, tipped with greenish-red. Spines often 

 absent, generally wanting in young stem-joints 

 when present, 2-3 cm. long, straight, somewhat 

 suddenly narrowed distally, often flattened to- 

 . wards the base, the lower parts yellowish, then 

 gradually passing from pale yellowish-brown to 

 reddish-brown distally. Spines never present 

 in quite young stem- joints and few on the older 

 ones persisting — these singly in twos and 2-5 

 cm. to 4 em. long. Spinules (glochidia) on a 

 yellowish coloured brush at the distal end of 

 areole, each about 5 mm. long, springing from a 

 little pale tomentum. These spinules may in- 

 crease with age, but are generally evanescent. 

 Flower-receptacles with a few weak spines on 

 the upper areoles, distal end somewhat festooned 

 and slightly costate also at each areole. Flowers, 

 yellow suffused with red towards the base of each 

 perianth segment — these being glossy and trans- 

 lucent. Pistil: Stigma eream coloured, 7 lobed; 

 stipes pale purplish-pink. Fruit not seen. 



This plant, as may be inferred from a com- 

 parison of descriptions, has much in common with 

 Dr. Roig's 0. tuna (1912, p. 39), which he con- • 

 trasts with 0. dillenii, and which he states is very 

 abundant in the Playa de Marianao, in Puentes 

 Grandes and Galabuzar, and in other places in 

 Cuba. 



Nopalea cochinelifera. This species was 

 commonly seen cultivated in various parts of the 

 island. 



Disease Occurrence. 



0. inermis, D.C., being so nearly related to 

 the Queensland prickly-pear — the Gayndah 

 variety especially — ^the plants found representing 

 it in the Pinar del Rio district were all carefully 

 examined in the hope of finding injurious in- 

 sects, &c., specificailly related to it, and, there- 

 fore, more likely to be useful in coping with our 

 pear than the insects associated, perhaps exclu- 

 sively, with other kinds not represented in Aus- 

 tralia. However, nothing resulted from the 

 search. 



Bud-destroying Lepidopterous Caterpillars. 

 In the Guantanamo district, in the neighbourhood 

 of Novali railway station, although the prickly- 

 pear plants (0. dillenii) were very numerous, 

 their growth had evidently come to a temporary- 

 standstill through the action of the ca,terpillar 

 of a small moth, related to if not identical with 

 Mimorista flavidissimalis, a serious enemy of 

 Opuntia in the United States. These insects had 

 attacked the growing shoots when they were still 

 quite young, with the result that they had with- 

 ered and decayed, the dry, shrunken, blackish 

 buds occurring on all sides, still on the plants, 

 or already fallen to the ground. Sometimes only 

 about half the shoots on a plant had been vic- 



timised, at other times almost all, so that green 

 shoots could be discovered only Avith difficulty. 

 As an instance of typical injury of this kind, that 

 had not proceeded as yet to its full length, we 

 may instance one affected shoot amongst many 

 similarly affected. Its terminal or free end was 

 shrunken and blackened. On both surfaces small 

 holes and patches of eroded tissue with a greyish 

 coloured surface were present. Three yellowish, 

 diminutive, lepidopterous larva were discovered, 

 two on one face and one on the other, protected 

 by a delicate web which covered them; one larva 

 being partly buried in the subjacent tissue. 



In examining a young green shoot to dis- 

 cover how the injury had been started, small ex- 

 cavations were found behind the true leaves (still 

 attached) in two places. In each of these were 

 two small pallid larvae that had evidently recently 

 hatched from eggs. In another instance, five of 

 these minute caterpillars were found gnawing at 

 the tissue behind a single leaf. Of course, to such 

 attacks as these the infested bud soon succumbs 

 under ordinary conditions. Sometimes, however, 

 after considerable surface damage is done, the 

 insect that has occasioned it disappears, having 

 possibly been removed by a wasp or other preda- 

 ceous insect, the young shoot then recovering, 

 but always showing subsequently, irregularity in 

 its outline. At times a young shoot is eaten quite 

 down to its thorny cushion-base in the areole from 

 which it has sprung. When older stem-joints, 

 especially terminals, are attacked, they remain 

 stunted with their borders more or less scarious 

 and indented, while scales or ribbons of blackish, 

 dry, gum-like matter may be present. It is very 

 evident that a marked effect may be exerted by 

 these insects in preventing the growth of the 

 plants which they have once assailed. 



Melitara sp. Injuries exactly resembling 

 those produced by Melitara prodenialis and its 

 allies in the United States of America were seen 

 in joints of 0. dillenii growing along the seashore 

 near Santiago. A considerable amount of de- 

 .struction had been occasioned, numerous dead 

 hollowed-out segments with insect excreta within 

 them and near them testifying to former activity. 

 M. prodenialis is the species occurring in the 

 adjacent peninsula of Florida. 



Chelinidca sp. ? Circular chlorosed areas 

 found on segments of 0. dillenii at Santiago sug- 

 gested the presence of a plant bug, the injuries 

 being similar to those caused by Chelinidea spp. 

 in Texas. 



Leaf-eating Ant. A single instance of an 

 old plant of 0. dillenii completely arrested in 

 growth through the action of an ant addicted to 

 consuming vegetable tissue, was met with near 

 Novali in scrub country. In this case the young 

 shoots were almost entirely eaten, so that the 

 fresh internal tissue became exposed, the ants 

 themselves being seen in operation. Older shoots 

 that persisted were small and stunted, and very 

 irregular in outline — a condition suggestive of 

 their having been damaged at an early stage in 

 I heir growth. The ant itself was a large one of 

 very lethargic habits, having two thorns on each 

 side of its cordate occiput and six arming the 

 crux, those of the prothorax being curved and 

 directed forward. 



