insects: tueik mouths. 171 



t,niination. You should choose a female Flea, partly 

 because of ber greater size, and partly because the pre- 

 datory M-eapons are better developed, in all these pierc- 

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

 Then you will lind it needful to amputate the bead, in 

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

 u'hich 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, Avitb one of those dissecting needles whose points 

 are ground to a cutting-edge. ISText, 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, Avill 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 brins: out dis- 

 tinctly the toothing of the mandibles 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 

 skill 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 



