98 



as yet. For this reason the student need not take this vein 

 into consideration in his studies of dipterous wings) ; the 

 division or not of cell J/, ; the presence or absence of cell 

 J/g ; the courses of the branches of the cubitus ; the extent 

 of the anal furrow ; and the course of the anal vein. 



Wing of a Tabanid. — A specimen of one of the horse- 

 flies, Tabanus^ will be given the student for examination. 

 Observe the subcostal fold ^ and note that this corrugation stiff- 

 ens the wing. 



Make a drawing of a mounted Tabanid wing, which will 

 be furnished on application to the instructor. Note that in 

 the mounted wing the subcosta is more or less concealed by 

 the radius, although the two veins are distinct, as was seen 

 in the unmounted specimen. Represent these two veins as 

 slightly separated in your drawing. 



In the description of this wing, state in what respect it is 

 more generalized than that of Rhyphus^ and in what respect 

 it is more specialized. 



Wing of an Asilid. — A wing of a robber-fly of the genus 

 Erax will be used as an example. Note a method of coa- 

 lescence of veins not exhibited by Rhyphus. 



Wing of a Bombyliid. — The example used is a wing of 

 PantarbgSy one of the bee-flies. 



Wing of a Scenopinid. — The wing used is that of a com- 

 mon window-fly, Scenopinus. 



Wing of an Empidid. — The wing used is that of Rham- 

 phomyia, one of the dance-flies. 



Wing of a Muscid. — The wing used is that of the com- 

 mon house-fly, Musca domestica. 



Wings of Dilichopodids. — The wings of two of the 

 long-legged flies will be used. The first belongs to the genus 

 Psilopus; the second to the genus Dolichopus. 



Wing of a Syrphid. — The wings of a fly of the genus 

 Syrphus will be used. Note the vein-like structure be- 



