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HYBRIDS AND DEGENERACY. 157 
They had returned to the type Pernyi, which is the stronger of 
the two. The other cocoons contained dead larve or dead pupe. 
At a meeting held at the Society of Arts on the 25th of April, 
1879, durimg the discussion which followed the interesting 
lecture delivered by Mr. Thomas Wardle, on the wild silks of 
India, I heard something about another hybrid which had been 
obtained in Bombay. The statement made by Mr. A. Rogers 
was as follows :—‘‘ A curious fact came under my notice. There 
was a man in Bombay, a barber, who made a most remarkable 
discovery with regard to Tusser silk. He showed me the 
produce of silk which had been spun by a hybrid worm, produced 
between the common Indian Tusser worm and what he said was 
the Japanese Yama-Mai. Whether that was the case I cannot 
say, but he certainly showed me two worms which were about the 
size of my little finger, and he informed me that the silk produced 
was much freer from tannin than the indigenous Tusser found in 
the jungle. He showed me some specimens, and, so far as I could 
judge, the hybrid silk was far superior to the other. Mr. Morris 
assured me that this hybrid would feed on the commonest trees 
in the country.” 
Mr. Wardle, in commenting upon the above statement, said, 
he doubted whether Mr. Rogers was correct, because the Yama- 
Mai was a Japanese species which was an oak-feeder, whereas the 
Tusser worm fed on very dissimilar food. Mr. Wardle said the 
Tusser cocoons contained no tannin or woody matter. 
With regard to Mr. Wardle’s assertion, I must say that the 
Tusser worm, like most other wild silk-producers, is essentially 
polyphagous, and that last year it was reared on oak by several 
entomologists, and on hornbeam by Mr. P. H. Gosse. 
Another hybrid between Yama-Mai and Pernyi was also 
mentioned in 1878, but, as for some reasons it has not yet come 
into the public domain, I can only quote from the discoverer of 
this wonderful hybrid, who is M. Bourdier, of Montboyer, France. 
After speaking of the merits of Yama-Mai, and the advantages 
enjoyed by Pernyi over Yama-Mai, he thus speaks of his Perny- 
Yama :—* This fruitful hybrid has over its parents the immense 
advantage of being perfectly hardy; it will resist a temperature 
of 0° centigrade (freezing-point), and will eat even dried-up 
leaves if they are not brittle. There is a second brood each year 
if the breeder, by artificial means, hastens the emergence of the 
