88 Objects for the Microscope. 



families ; the third joint of the antennae, always the largest 

 in this family, enables us to recognise a true Musca at once. 

 After that we must look at the wing, which varies very 

 much in the number and position of its veins. 



There are many house-flies. The Musca domestica will 

 show the prsebrachial vein, forming a rounded obtuse angle 

 at its flexure, nearly straight from thence to the tip ; the 

 discal transverse vein nearly straight, parted from the border 

 by more than half its length. 



This little wing makes 600 strokes a second, carrying it 

 five yards ; if alarmed, can increase its velocity to thirty- 

 five feet in a second. 



WING OF BLUE-BOTTLE FLY, 



(Musca Vomitoria,) 



will show the Discal transverse vein with two distinct 

 curves, parted from the border and from the flexure of the 

 prsebrachial by hardly one-third of its length. The an- 

 tennae of this fly have the third joint remarkably long, and 

 furnished with peculiar organs of smell. (See Antennae of 

 Blow-fly.) 



WING OF SYRPHUS, 



not one of the Muscidse, or true flies, and therefore a good 

 example of a beautiful variety. The Syrphidse are a nu- 

 merous family, comprising thirty-one genera; they are 

 mostly seen hovering over flowers, vibrating their wings as 

 they pause awhile, then darting with rapid flight a short 

 distance only, and becoming stationary again. Many of 

 the species make a humming noise like a Bee, and are 

 mistaken for either Bees or Wasps. 



The veining of this wing is an excellent lesson. The 

 Costal vein ends just before the tip of the wing, and 

 receives the Radial, or Cubital; for both these veins are 

 not always present in the Syrphus wing. 



The Mediastinal is very distinct ; a transverse vein con- 

 nects the Cubital with the Prcebrachial near the margin. 

 But the chief distinction lies in one or two spurious veins, 



