180G.] 



201 



A (Z) I is a quadrilateral sheet of glass, of the width of the box, fixed at the angle 



shown in the figure. 

 E S is another piece of glass of the shape of a triangle with the apex cut off. 

 A E S Z (represented by the lines A Z, E S and dotted lines A E, Z S) are two other 

 bits of glass shaped like E S— the four pieces A I, A E S Z, E S, and A E S Z 



(No. 2) being arranged and fixed 

 a ^-^^ (as shown in accessory perspec- 



tive figure) in such a manner 

 that, viewed from the point V, 

 they form a hollow four-sided 

 pyramid, the apex of which is 

 wanting, as shown at Z S in 

 both figures.* 



T, V, and X are arrows indica- 

 ting the direction an insect 

 ^ flying towards the lamp K must 

 unavoidably take. 



N.B. — Besides the above, 



it is recommended that the parts 



of the sides of the box corresponding with the triangles A E I should be lined 



with glass ; and a duphcate drawer, fitted up in every way exactly like the 



drawer M, should be prepared in readiness for use. 



To set the trap, all that is necessary is — 1. To light the lamp. 

 2. Push in the drawers M and N. 3. Pull out the glass slide O. 



As seen by the directions of the arrows T, V and X, any insect 

 flying towards the lamp K must go into the trap, even though its flight 

 be not directed to the central aperture Z S ; once in, it must go down 

 to " the dark regions," where soon becoming snugly ensconced in some 

 dark corner of the drawer, or on parts of the Venetian apparatus out 

 of the focus of the light, it will not, avers Mr. Glover, again risk getting 

 into the glare of the lamp, but even if it do, the odds against the escape 

 of the captive are something fearful. 



— facilis descensus Averni ; 



Sed revocare gradus 



Whenever it may be considered advisable to examine the contents 

 of the trap, the slide O should be pushed in, the drawer M removed, and 

 the duplicate quickly inserted in its place, a procedure which, without 

 interfering with the influx of visitors, allows us to leisurely operate 

 upon our captures by cliloroforming them with the aid of the little 



* If Young Euclid will now ohlitci'atn the line Z I, and from some point between A and H draw a 

 line to I. anoiher idea will be repreisentcd wliicli, though rendering the escape of the entrapped all but 

 imposuiblo, lias certain drawbacks. 



