ZOOLOGY AND BOTANY, MICEOSCOPY, ETC. 



521 



to repeat the adjustment of tlie mica-plate it is advisable to catch a 

 number of large or a number of small insects at a time, which is not 

 difficult to arrange, considering their immense numbers and variety." 

 An insect-cage supplied to us by Messrs. Beck is shown in fig. 1U9. 

 It consists of four parts. A is a ring, open at the bottom but closed 



Fig. 109. 



at the top by a glass plate, and having an aperture on one side. B 

 consists of two rings similar to A, one sliding within the other and 

 forming a box. Small insects can pass into the box through apertures 

 in each of the rings, but this can be closed at pleasure by revolving 

 one of the rings on the other. C is a frame into which A and B are 

 placed, and having also a hole through the centre divisions. 



A and B being in position in the frame C, and the apertures 

 arranged so that there is a passage from the one box to the other, 

 A is placed over an insect which it is desired to secure for observa- 

 tion. The bent brass plate D is then slipped under it so that A is in 

 darkness and B in the light. The insect will then pass from A to 

 B which can be removed for examination, the aperture being closed 

 by rotating the rings. 



If the box B were arranged, as could easily be done, so that the 

 space between the top and bottom could be reduced to suit the size 

 of different insects, we think the apparatus would be decidedly 

 superior to that of P. Miiller as it could then be placed on the stage 

 of a compound Microscope and any mode of illumination could be 

 used, transparent as well as opaque. 



A somewhat similar contrivance was suggested by Mr. P. N. 

 Tillinghast * to obviate the difficulty of introducing a third or even a 

 second insect into a box without letting one of those already caught 

 escape. It consists of a box divided into two compartments of unequal 

 size by a sliding division, the end of the larger compartment being 

 of glass. The new capture is placed in the smaller compartment and 

 the lid of the box being closed the slide is withdrawn and the insect, 

 observing the light through the glass of the larger compartment, 

 passes into it. On again closing the slide the box is ready to receive 

 further supplies. 



ToUes's Centering Stage. — The stage shown in fig. 110 was found 

 among the effects of the late Mr. E. B. Tolles after his death, and is 

 an example of one of the many efforts made by him to improve the 

 mechanism of the Microscope. It was apparently devised to meet 



* Amer. Joura. Micr., vi. (1881) pp. 133-4 (2 figs.) 



