Dr. C. Murchison on the White Secretion of Flata limbata. 359 



structure, but were fibrous-looking, and so soft as to retain the im- 

 pression of the finger, It presented peculiar microscopic characters, 

 which had been described and figured by Mr, Quekett in an appendix 

 to Mr. Hanbury's paper published in the * Pharmaceutical Journal/ 

 When examined with a power of 250 diameters linear, it was " found 

 to consist of a series of short filaments or cylinders, some of which 

 are straight, but others more or less curved ; within each cylinder is 

 a tubular cavity, extending throughout its whole length. The dia- 

 meter of the cylinders is on an average 4-^^th of an inch, whilst 

 that of the tube within varies from y gVo*^ *° 8^oo"^b." Mr. Quekett 

 had found similar tubular filaments in the cocoons of the Cochineal 

 insect. The specific gravity of the crude wax had not been ascer- 

 tained, but the melting-point of a purified wax obtained from the 

 crude substance had been shown by Mr. Hanbury to be 182°*75 Fahr, 

 It did not dissolve, or at all events but very sparingly in alcohol, 

 aether, or solution of caustic alkali, but it dissolved readily in naphtha 

 and vegetable oils, uniting with the latter to form a solid white mass. 

 When melted, it formed a clear, colourless liquid, which became 

 opake white on cooling, and was then found to have lost its tubular 

 structure, and to be composed of acicular crystals arranged in 

 stellate masses, hke those produced by the commercial wax when 

 similarly treated. From these characters, as well as the evidence 

 of Mr. Lockhart of Shanghae, Dr Murchison thought that there was 

 good reason for coinciding with the conclusion arrived at by Mr. 

 Hanbury, that the Coccus Pela is a source of the commercial wax. 



3. The characters of the white appendages of the Flata limbata 

 were then considered. Close inspection showed that these appen- 

 dages were of two sorts. First, there was on each insect a small 

 tuft or brush of minute white hairs, adhering firmly to either side of 

 the insect's body, and distinguished from the great bulk of the white 

 appendages by their smaller size, greater slenderness, less opacity, 

 and greater strength, admitting of being handled with perfect im- 

 punity. These filaments under the microscope presented the 

 ordinary characters of the hairy appendages often found on insects, 

 with a remarkable tendency to split up at their distal extremities. 

 The greater bulk of the white appendages were thicker, longer, and 

 more opake than the preceding. They were but loosely attached to 

 the surface of the insect's body, and extremely delicate and fragile, 

 so that the slightest touch with the point of the finger reduced them 

 to a fine white powder, and hence was explained the fact, that the 

 leaves and branches uf)on which these insects occur, become com- 

 pletely whitened by a white powdery substance in the manner de- 

 scribed by Sir G. Staunton. On microscopic examination they pre- 

 sented a beautiful appearance of spiral structure. When one of the 

 appendages was compressed with care between two glass plates, and 

 examined under a power of 250 diameters, it was found to consist 

 of a mass of spiral threads, with their long axes running in the same 

 direction. The slightest friction of the surfaces of the glass plates 

 broke up these threads into fragments more or less minute, and if 

 the friction was continued, they were almost entirely converted into 



