observed in Bombyx Cynthia. 491 
two generations in the year, and passes the winter inactive in 
cocoon: ficini has from seven to twelve broods, and is in a state 
of constant reproduction, winter as well as summer.” 
All these differences summed up give to Ricini a smaller size 
than Cynthia, a suppression of coloration in the egg, larva and 
imago, some difference in the cocoon, an absence of spots in the 
larva of Ricini which are present in that of Cynthia, and a blurred- 
ness of marking in the imago, with the presence of numerous 
white woolly tufts on the abdomen. ‘These two latter charac- 
teristics, together with a deficiency in size and an absence of 
coloration, have been exhibited in the varieties of B. Cynthia bred 
by me. Two other chief characteristics are, Ist, a difference in 
the cocoon, which is much more woolly in Ricini, harder and 
closer in Cynthia; but this is due to the presence of more gum 
(and that may be due to the influence of the food-plant) in the 
cocoon of Cynthia, which enables the larva to bind the threads 
down more closely; 2ndly, the absence of black dots in the larva 
of Ricini which are present in Cynthia; but unless some other 
stronger evidence is brought forward to show that the larve differ, 
I cannot admit that dermoid differences, which are the least of all to 
be depended upon in differentiating species, can alone constitute 
Ricini distinct from Cynthia.* As to the alleged habit of B. Ricint 
breeding five or eight times annually, or oftener, in Bengal, and B. 
Cynthia only once in Assam, England, &c, we have this fact, that 
in 1865, in Paris, there were four generations of B. Cynthia, which 
proved that under a suitable temperature that insect is, like B. Ricin?, 
many-brooded. Looking to the habitat of B. Ricini, Bengal, and its 
food-plant, Ricinus, I see no ground for separating the species; I 
* The more especially as, on referring to Mr. Moore's “Synopsis of 
Asiatic Silk-producing Moths,’’ I find it stated, p. 32, that, according to 
Mr. Hugon, see “Journal A. 8S. Bengal,” vi. pp. 28, 24, the caterpillar of 
the Eria, which is the local name for the Bombya Ricini, “in a domesticated 
state in Assam, as it increases in size, becomes of an orange colour, with six 
black spots on each of the segments; after the second moult the colour of the 
body becomes lighter; in some approaching to white ; in others to green, and 
the black spots gradually become of the colour of the body; after the fourth 
moult the colour is a dirty white or a dark-green; the white caterpillars in- 
variably spin red silk, the green ones white. The Eria feeds on the Ricinus 
communis, and gives twelve broods in the year.’’ If, then, we have a history 
of spots apparent at birth suppressed after an interval, the argument that 
Cynthia and Ricini larve are distinct, because the one has spots and the 
other has not, becomes considerably weakened. Again, M. Personnat states 
that larve of B. Yamamai, fresh from Japan, are flecked laterally with silver 
spots, whereas, when naturalized in France, they lose all metallic tint. 
