SCIENTIFIC NOTES. 237 



at that moment has every character of the imago. The epidermal 

 secretion which immediately takes place, and which, hardened, 

 becomes the chitinous covering which we call the pupa case, is an 

 external structure, and perfectly separate and distinct from the 

 immature imago which it envelops, although the separation only 

 becomes absolute as scale development proceeds and is matured. 

 It must be perfectly clear, therefore, that the slightest injury at the 

 moment of change, will cause the secretion which forms the chitinous 

 case, to be imperfect, the membrane will probably be injured, the 

 scale development at such point of injury fails to become normal, and 

 malformation is the natural result. Holes in wings are, however, oc- 

 casionally due, to minute parasites, which, although sapping the 

 vitality of the host, do not cause death, and the parasite escaping 

 from the pupa case, before the imago, leaves a tiny hole through 

 all those portions of the wing (membrane, etc.), through which it had to 

 make its exit. Total absence of wing development, which we frequently 

 find, appears to be due to the first cause (injury at pupal change). 



But disease not only produces monstrosities and aberration of 

 form, it also produces variation in markings. Cripples are well 

 known, owing to imperfect cell-development, to tend to have a 

 coalescing of spots and markings, and dots are frequently formed into 

 more or less imperfect bands in crippled specimens. I bred a long 

 series of Arctia menthastri from pup» sent me from Scotland. They 

 were all strongly marked, one being an exceptionally fine radiated 

 form (var. walkeri). However, many never emerged, and, on opening 

 the dead pupae, I found nearly all were of the dark radiated variety. 

 It would appear that those pupge which were too weak to emerge had 

 a greater tendency to vary than those that emerged. I may add that 

 many of this brood had more or less malformed wings. Here, I feel 

 satisfied, disease was the general cause of the variation. It would be 

 interesting to have other facts. — J. W. Tutt. December, 1890. 



The malformation on the margins of the wings, mentioned by 

 Mr. Griffiths as occurring in Z. dispar, is probably due to interbreeding. 

 It has been more particularly noted in L. dispar and Macaria notata 

 than in any other species. — Sydney Webb, Dover. November, 1890. 



Sudden Development of the Wings of Chesias spartiata. — 

 I have been breeding C. spartiata and have noticed four nights in 

 succession, that a specimen has been out, running rapidly over the 

 muslin top of the box, but with tiny unformed wings. On looking 

 into the box in the morning, the appearance was just the same until 

 about 8 or 9 a.m., when a pair of long pointed wings would suddenly 

 drop. Is this usual ? and why do the wings remain so long un- 

 developed and then develop suddenly? — E. Bazett, Reading, 

 November, 1890. [This is so opposed to our ordinary ideas of wing- 

 development, that it would be interesting to get further information as 

 the result of observation. — Ed.] 



Glands on the Thorax of Certain Lepidoptera. — Has any 

 one noticed that Liparis salicis has the power, when annoyed, of 

 ejecting a pale greenish or yellowish fluid from (apparently) glands, 

 situated on the thorax, above the eyes ? I have specially noticed this 

 lately. — C. Fenn. Juh\ 1890, 



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