Objects for the Microscope. 149 



STENOPTERTX. 



This should be looked for on swallows: you may find them 

 abundantly in nests of the young birds. They run very 

 quickly, but do not attempt to fly, although they have 

 wings, and are good examples of another genus of the Hip- 

 poboscidse. 



Here we find a difference in the male and female ; the 

 former having long narrow wings, ciliated in front, the 

 costal vein more than two-thirds the length of the wing, and 

 longitudinal veins crowded close to the costal. The female 

 has short triangular wings ; the rest of the body very like 

 that of Melophagtis. 



ORNITHOMYIA. 

 (Parasite of Birds.) 



A green and tawny fly, more perfectly winged than the 

 preceding genera, but seldom, if ever, using the wings, and 

 running with great swiftness amongst the feathers of all birds. 



NYCTERIBIA. 



This is a rare parasite, but quite worth seeking, upon 

 bats. The head is thrown back in an extraordinary manner ; 

 the mouth has a large bulb-like organ, from which proceeds 

 a horny style. It has no wings; the claws are strong, 

 dilated beneath ; and the abdomen is terminated by two 

 styles. There are specimens of this in the British Museum. 



CHELIFER. 



This parasite attacks flies. I have seen a common fly 

 run wildly about the window-pane, shaking itself violently, 

 and apparently in great distress. Upon catching it, I 

 found a small scorpion-like creature fixed upon one of its 

 thighs, by a pair of tremendous claws, hardly could it 

 be detached for examination, and then it ran quickly like a 

 crab, sideways. The Chelifer belongs to the Trachean 

 Arachnida, that is, they breathe by means of trachea and 

 spiracles, and not, as the higher order of spiders, by lungs, 

 or internal gills. They have eight legs, two long palpi 

 armed with claws ; the eyes are at the side of the thorax, 

 and the flat abdomen is jointed. 



