Objects for the Microscope. 69 



the two serrated mandibles work rapidly up and down, the 

 sheath folds backward, the pressure of the lancets causes a 

 little poison-bag, situated at the base of the proboscis, to 

 emit one drop of acrid matter, and when the little creature 

 has sucked our life-blood, and her small body is distended 

 and crimsoned with her draught, she flies off like a winged 

 ruby in the sunlight, that little poison-drop rankling in the 

 wound and causing our after uneasiness and irritation. It 

 is worth the slight annoyance, however, to watch the process 

 of her feast. With a pocket lens we can see the working 

 down of the lancets, and the up-flowing of the blood into 

 her stomach. 



The shrill buzz of the Gnat, like a fairy clarion, is peculiar 

 to the female, and only heard when she is bloodthirsty. 

 Her delicate wings then vibrate 3,000 times in a second, 

 and are supposed to cause this sound by the friction of their 

 bases against her body. Her eyes, which quite cover her 

 head, and the long fourteen-jointed antenna weaving to and 

 fro, make her a beautiful object, in spite of her unpleasant 

 propensities. 



PKOBOSCIS OF ASILTTS. 



The Asilus is one of the Diptera (Flies) the largest and 

 fiercest of them most frequent in sandy situations. They 

 flit about in the hot sunshine, pouncing upon all smaller 

 flies Beetles and Hymenoptera, Ichneumon flies, &c. 

 holding them between their fore legs, and plunging their 

 sharp lancets and fleshy tongue into the softest part of their 

 prey. The colour of these flies is mostly tawny, gold- 

 coloured, or reddish-yellow ; the wings finely-veined and 

 clouded at the edge ; the body long and narrow. The 

 larva lives in the earth : it has twelve segments, and 

 changes to a spiny pupa, from whence the Fly emerges in 

 June. 



PROBOSCIS OF EMPIS-FLT. 



The Empis is often called the Snipe-fly, from its remark- 

 able labrum, which really resembles a Snipe's beak. When 

 at rest it is folded close to the breast, but very frequently 



