490 Dr. Wallace on some Variations 
tion blurred, or less distinct than in the normal insect. Nos. 18 
and 23 are specimens of the most vigorous and healthy dwarfs. 
With these specimens before us, it is evident that great variation 
occurs in this species, dependent on food-plant, temperature, 
season of the year, and influence of light, It varies greatly in 
size and in coloration. 
The question may be asked, Are Bombyx Cynthia and B, Ricini 
distinct species? There is also a third species or variety, BD. 
Guerinii, described in Mr.’ Fred. Moore’s Catalogue from a few 
specimens extant; but until we have many more examples of this 
insect sent over, with a description of the larva, showing that it 
differs from that of B. Cynthia, I should be inclined to believe it 
only a variety of that insect; for I can, I think, produce varieties 
of the latter, possessing some or all the traits of B. Guerinii, 
except the entire suppression of the lunule, and I expect some day 
to witness that among my dwarfs. Again, the differences recorded 
between Ricini and Cynthia, according to Mons. Guérin-Méneville, 
are as follows :— 
1. ‘* The egg of the true Cynthia is white, but its shell is covered 
with little brown or black particles of gum, which give it a spotted 
look. That of Riczni is entirely white, is smaller, and less 
heavy.” 
2. “ The caterpillar of Cynthia has on each segment four black 
spots, and when full grown is of a beautiful emerald-green, with 
its head, claspers and the last segment beautifully marked with 
yellow. That of Ricini has no spots, and is uniformly of a pale 
azure.” 
8. “ The cocoon of Cynthia is naturally of a hempen-grey 
colour; that of Rictni of a vivid red, and weighs less.” (Yet I 
have had many cocoons of Cynthia, especially of the earlier and 
later growth, or if fed on other than Ailanthus leaves, and there- 
fore not maturely developed, more or less of a rusty-red colour.) 
4, The imago of Cynthia is larger, its abdomen is yellow above, 
having little white separate tufts of scales. The large transverse 
white line beyond the middle of the wings is bordered externally 
by a broad rosy band. The transparent lunule in the four wings 
is greater, and the brown space above the lunules in the upper 
wings is much longer (often twice or thrice) than it is broad. In 
Ricini the belly is entirely white, instead of being rosy the trans- 
verse band is of a dull grey, the lunules are shorter, and the 
brown space above in the upper wings is shorter, hardly as long as 
itis broad. In order to complete the comparison, Cynthia has but 
