18 COLLECTING AND PRESERVING INSECTS. 



(e), 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 the excrement and frass which fall to the 

 ground ; while the insects in transforming enter the ground or 

 attach themselves to the sides or the cap, according to their 

 habits. The most convenient dimensions I find to be 12 inches 

 square and 18 inches high : the cap and the door fit closely by 

 means of rabbets, and the former has a depth of about 4 

 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 6 or 8 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 breeding: 

 of a great number of species, as several having different habits 

 and appearance, and which there is no danger of confounding, 

 may be simultaneously fed in the same cage. I number each 

 of the three parts of each cage to prevent misplacement and to 

 facilitate reference, and aside from the notes made in the note- 

 book, it will aid the memory, and expedite matters, to keep a 

 short open record of the species contained in each cage, by 

 means of slips of paper pasted on to the glass door. As fast 

 as the different specimens complete their transformations and 

 are taken from the cage, the notes may be altered or erased, or 

 the slips wetted and removed entirely. To prevent possible 

 confounding of the different species which enter the ground, it 

 is well, from time to time, to sift the earth, separate the pupae 

 and place them in what I call imago cages, used for this 

 purpose alone and not for feeding. Here they may be ar- 

 ranged, with reference to their exact whereabouts." 



The object is to keep the food-plant fresh, the air cool, the 

 larva out of the sun, and in fact everything in such a state of 

 equilibrium that the larva will not feel the change of circum- 

 stances when kept in confinement. Most caterpillars change 

 to pupae in the autumn ; and those which transform in the 

 earth should be covered with earth, kept damp by wet moss, 

 and placed in the cellar until the following summer. The col- 

 lector in seeking for larvre should carry a good number of pill- 

 boxes, and especially a close tin box, in which the leaves may 

 be kept fresh for a long time. The different forms and mark- 

 ings of caterpillars should be noted, and they should be drawn 



