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The stripping of the bark from newly-felled trees at once kills 

 actively feeding larvae, since they require the protection of the bark, 

 but those that have finished feeding and have penetrated into the 

 solid wood are unaffected by this measure. Infested trees that are 

 not seriously weakened by the presence of the larvae should be at 

 once utilised as mine props, or for the making of charcoal, or as firewood. 



Moore (J. B.). The Cattleya Fly. — New Jersey Agric. Expt. Sta., New 

 Brunswick, Bull. no. 308, 2nd October 1916, 12 pp., 2 plates. 

 [Received 30th May 1918.] 



Isosoma orchidearum, Westw, (cattleya fly), which has been imported 

 into New Jersey from South America, is the most serious enemy of 

 certain species of orchids. The growing of seedling orchids has not 

 proved practicable commercially and each plant must therefore be 

 imported, consequently the presence of this Chalcid, which weakens 

 and frequently destroys the plants, is of the greatest importance. 

 Very little has been known of the fife-history of the pest, and while 

 still incomplete, the author's investigations have added considerably 

 to that knowledge. The egg is laid under the epidermis, usually of 

 the pseudo-bulb or young leaf-buds, and occasionally of the leaves 

 and of the rhizomes. It seems likely that only those eggs mature 

 that are deposited in growths less than a year old. The length of the 

 various stages in the life-history are not known, but the time required 

 from oviposition to emergence is at least 3 months in winter, probably 

 from 4 to 6 months would be more correct, but this period varies 

 greatly with the temperature. 



The larvae injure the plant by burrowing out a cavity in the interior 

 of the young buds or pseudo-bulbs, and feeding on the soft tissue. 

 As soon as the burrow is made the growth of the plant is weakened, 

 so that for 2 or 3 years it produces very poor blooms or none at all. 

 Several larvae may be present in the same pseudo-bulb, in which 

 case the cavities may join up and as many as 10 larvae may be in the 

 same cavity. The plant swells up in the vicinity of the cavity and 

 by this means the injury can be recognised. The larvae pupate in 

 the cavity, the adults emerging by gnawing a small circular hole 

 through the epidermis. The intensity of sunfight«and the tempera- 

 ture of the house greatly influence the time of emergence and ovi- 

 position. Emergence usually occurs on a warm, sunny day and may 

 then be followed by oviposition on the day following, while a few cool, 

 cloudy days would delay the process, or check the rate of oviposition. 

 In less than one day after emergence the insects may have infested 

 a dozen or more healthy plants. The adults live only 4 or 5 days 

 and during this time one female probably lays rather more than 

 50 eggs. Very vigorous plants are perhaps somewhat immune from 

 attack, as the quick growth of the bud crushes the larvae inside. Some 

 varieties of Cattleya are more susceptible to attacks by 7. orchidearum 

 than others ; Cattleya mossiae and C. gaskelliana suffer very few injuries, 

 while C. labiata, C. percivaliana, C. gigas and C. trianae are badly 

 afiected. 



The remedial measures that have been recommended for I. orchi- 

 dearum include fumigation, spraying, injection of insecticide into the 

 infested portions and destruction of the infested parts. Fumigation 



