12 THE entomologist's llECOilU. 



to form a second dark cocoon, or in other words, was unable to supply 

 the necessary colouring matter, to darken the silk which it spun. 



As to how the larva applies the intestinal waste remaining in its system 

 at the time of spinning, for the purpose of colouring its cocoon, I can 

 only form suggestions. The excretion must be made from the anal orifice, 

 I think, and not from the oral (although the latter is more than possible). 

 The difficulty of accepting the hypothesis that the colouring matter is 

 excreted from the oral orifice suggests itself to me because the normal 

 colour of the silk which is spun as a basement on which to build the 

 cocoon, is apparently always white, and I take it that all the silk spun is, 

 in the same way, white, and that the colouring matter is injected after- 

 wards. If further observation should prove the silk spun is not always 

 white, I should prefer to suppose that the oral orifice was used for the 

 purpose of excretion. If on the other hand, excretion takes place from 

 the anal orifice, the secretion may be poured out in small quantities in 

 very fluid form, after the silk is spun, to darken the parts already formed, 

 in the ordinary manner of fluid intestinal excretion. 



I only record one other observation, and that was made when I 

 thought I had finished my observations. I left the larvse which 

 remained in the bags, to spin up or die as they thought fit, and quite 

 nine-tenths of the cocoons formed by the remnant were paler than one 

 would expect in all the bags, some in the dark bag being quite white, 

 showing that the starvation element was a stronger one in the direction 

 of the formation of a pale cocoon than was the dark environment, in 

 the direction of the formation of a dark cocoon. 



In conclusion, my experiments with Halias chlorana have satisfied me 

 that, within certain comparatively narrow limits, this species has the 

 power of forming a cocoon which shall respond to its environment ; 

 but that the formation of an excessively dark cocoon in nature shows 

 a strong tendency to some form of disease ; in which the intestinal 

 excretion becomes very dark ; whilst the formation of an absolutely 

 white cocoon, given that the larva is healthy and has a plentiful supply 

 of food, is almost a physical impossibility, although in response to 

 environment it is possible (and probable) that a comparatively pale one 

 might be formed. I also conclude that the colouring matter is an 

 intestinal waste product, the colouring of which produces the variation 

 in the colour of the cocoons, and the total absence of such waste, 

 results in the production of an absolutely white cocoon, and comparative 

 absence, a comparatively white one. — J. W. Tutt. October, 1891. 



SiURRENT NOTES. 



^^ 



The Entomological Society of London suggests dropping the July, 

 August, and September monthly meetings, and substituting three extra 

 meetings in the summer months. 



The Title-page to Vol. II. of The Entomologisf s Record, which could 

 not be printed in time to be published with the December number, will 

 come 6ut with the Special Index. 



The City of London Entomological Society has taken much more 

 convenient rooms at 33, Finsbury Square. The Council call the atten- 

 tion of Entomologists to the list of papers that are to be read at the 



