INSECTS : THEIE MOUTHS. 171 



amination. You sliould clioose a female Flea, pai-tly 

 because of her greater size, and partly because tbe pre- 

 datory weapons are better developed, in all these pierc- 

 ing and sucking insects, in the females, — true Amazons. 

 Then you will find it needful to amputate the head, in 

 order to get rid of the front legs, the thick thighs of 

 which else impede your sight of the mouth, being pro- 

 jected on each side of it. And this is a delicate opera- 

 tion : it must be performed on a plate of a glass, under 

 a lens, with one of those dissecting needles whose points 

 are ground to a cutting-edge. Next, having served the 

 head, you must place it in a drop of water, between the 

 plates of your compressorium, the graduated pressure 

 of which, by means of the screw, will cause the organs 

 of the mouth to open and expand separately. Finally, 

 you must have a good instrument, and a high power : 

 less than 600 diameters will not avail to bring out dis- 

 tinctly the toothing of the mandilles and labrum / and 

 even then you will need delicate manipulation and a 

 practised eye. But the object is worthy of the care 

 bestowed upon it. 



Once more. Let us submit to examination the 

 complex case of instruments wherewith the Gnat per- 

 forms her unwelcome yet skilful surgery. I say " her," 

 because among the Gnats, as among most of these 

 puncturing insects, it is the females only who attain 

 sldll in the phlebotomic art, the males being innocent 

 of any share in it, and being indeed unprovided with 

 the needful implements. 



Here is a large specimen, resting with elevated hind 

 legs on the ceiling, and now in alarm off with shrill 

 humming flight to the window. I decapitate her with- 

 out compunction, as it is but a fair penalty for her 



