512 VARIETIES. 



the possessor a few days afterwards, and " made such inquiry as to 

 be fully satisfied that no other insect of the kind, in either state, 

 could have gained admission into the box where the larvae (? larva) 

 had been deposited to undergo its transformation." Here all is clear 

 and intelligible : a single larva formed its cocoon, and two moths 

 emerged from it. Now, although we are bound to believe that which 

 is put forth in the Magazine, gravely, and without comment, or even 

 a single ! (which surely implies that it is almost a matter of course, 

 as when a really wonderful thing is given three notes of admiration 

 can be afforded; see Vol. I. p. 318,) yet I think we have a right to 

 request that you will endeavour to obtain some more particulars, to 

 enable dull brains, like mine, to comprehend it. Had the larva two 

 heads, and two sets of legs, or only one of each ? Is it known 

 whether the division took place when the larva changed to pupae, or 

 when the pupa changed to moths ? Is the cocoon preserved ? Has 

 it been opened ? Does it contain one or two exuviae ? If one, what 

 is its appearance ? generally the head, eyes, antennae, wings, feet, 

 and segments of the abdomen may be traced on the skin of the 

 pupa. How are they arranged here ? If the possessor cannot 

 answer these questions, pray do try to induce some of your learned 

 friends to give us a plausible, probable, or even possible theory, that 

 we may have some ground for our faith. My old-fashioned preju- 

 dices have said that the successive changes in the larva, and from 

 larva to pupa, and from pupa to imago, are but as the casting off of 

 so many garments, within which the imago was from the first 

 encased, every part in its appropriate place, as I have often fancied I 

 could see in the Lepidopterous pupae. — Are these mere fancies ? 

 Does the larva contain merely an homogeneous pulp, which, if it be 

 but sufficiently abundant, may be elaborated into two flies instead of 

 one ? If not, then how are we to suppose that the two animals were 

 disposed in the one skin ? Were they placed head to tail, or side by 

 side, or one within the other ? Had the last been the case, one would 

 think the inner one would have burst the other when making its 

 escape — they must therefore have been severally contained within the 

 caterpillar's skin. Had it a double set of spiracula, or how could 

 breathing be carried on by both 1 Must it have had two mouths, or 

 could one communicate with two alimentary canals ? Is it probable 



but so many questions suggest themselves that I shall tire your 



patience ; and, as I am sure you know all that I would ask, I will 

 conclude by again begging that you will, by some means or other, 

 gain further information on so very interesting a subject. 



I am, Sir, yours, &c. 



Birmingham, February, 1836- THOMAS MARSHALL. 



