784 On the Origin of the Lac. [ November, 
the bark. If it be a female, and I shall take cognizance here only 
of the female insect, as it grows older it forms its eggs, and the 
entire insect develops into a shapeless sac enveloping these eggs. 
Within this sac is developed at the same time a purple-red gelat- 
inous mass which contains the eggs and perhaps serves as food 
for the young insects. By this time, also, the numerous sacs 
are entirely enveloped in a heavy mass of the lac-resin. The 
cellular structure of the latter is caused by the soft sacs of 
the females enclosed in the hard resin. When the young are 
hatched, they bore a hole through the back of the mother-sac and 
through the resinous envelope and escape, fix themselves to new 
portions of the plant and the life-history begins again. 
Now, although I am by no means confident that the Coccus 
which forms our Arizona lac is identical with the Coccus lacca, 
yet I think that I can show that the resemblance is sufficiently 
close to enable a course of reasoning on this insect to apply to 
the Indian species as well. In the first place the very great chemi- 
cal similarity of the Arizona gum to the Indian, as shown at a 
meeting of the California Academy, is a presumption to this effect. 
In the next place, the coarse cellular structure of the resin, the 
enclosed sacs with the eggs and purple juice, formed in the Ari- 
zona product and agreeing with the descriptions of the India lac, 
are another set of facts strongly confirmatory. Lastly, the 
_ specimens of lac from Arizona with the holes bored in it by the 
escaping insects, furnish additional evidence of close agreement. 
` Very recently also I have received from Mr. J. A. Culbertson, of — 
Arizona, specimens of the young insects affixed to the twigs. 
_ They are minute scale-bugs of a red color, with indistinct mark- 
- ings across the back. In size I should roughly estimate them at : 
one-fiftieth of an inch in length and half that in width, though 
some are even smaller. No doubt could exist but that they 
belong to the Coccide, and that they are very similar in develop- 
ment and life-history to the Coccus lacca. Hence I think that any 
general deductions from examination of the Arizona lac will 
apply equally well to the India product, especially as all descrip- 
tions of the products of the insect—lac-dye and lac-resin—seem 
to coincide. 
We notice first that resin is developed only by the action of 
this insect. No similar product can be obtained from the plant 
by other means. This is stated of the India lac in the sentence — 
