APPENDIX. 183 



To the centre of the zinc pan is soldered a zinc tube (d) 

 just large enough to contain an ordinary quinine bottle. 

 The zinc pan is filled with clean sifted earth or sand (f), 

 and the quinine bottle is for the reception of the food- 

 plant. The cage admits of abundant light and air, and 

 also of the easy removal of excrement and frass Avhich 

 falls to the ground; while the insects in transforming 

 attach themselves to the sides or the cap according to 

 their habits. The most convenient dimensions I find to 

 be twelve inches square and eighteen inches high ; the 

 caj) and the door fit closely by means of rabbets, and the 

 former has a depth of about four inches to admit of the 

 largest cocoon being spun in it without touching the box 

 on which it rests. The zinc pan might be made six or 

 eight inches deep, and the lower half filled with sand, so 

 as to keep the whole moist for a greater length of time. A 

 dozen such cages will furnish room for the annual breed- 

 ing of a great number of species, as several having dif- 

 ferent habits and appearance, and which there is no dan- 

 ger of confounding, may be simultaneously fed in the 

 same cage.'' 



The best success will always attend efforts to place the 

 prisoner in conditions as nearly natural as possible; but 

 in rearing out-of-doors it is more difficult to keep track of 

 your charges, and they are of course more subject to their 

 natural enemies, which are numerous and vigilant. More- 

 over it is then nearly impossible to obtain the cast-off 

 heads of each moult, which are well to preserve for com- 

 parative study at leisure, or to complete the tangible 

 marks of the life-history of the insect. 



Such caterpillars as construct nests in which to live 

 when not feeding, and especially such as then live a great 

 while in the caterpillar state, as for instance nearly all the 

 skippers, are the hardest to rear satisfactorily apart from 

 their natural homes; they do not like to live in a dried-up 



