No. 377-] THE WINGS OF INSECTS. 339 
each other at the margin of the wing. In Thereva (Fig. 32) 
an approximation of the ends of these veins has taken place, 
which results in a narrowing of the outer end of cell M}. In 
Sc :R, R2+3 Rits 
Ea 
mA 
~D 
Cu,t+ ist A 
Fic. 35. — Wing of Conops. 
Eulonchus (Fig. 33) the tips of the two veins coalesce, and cell 
M} is thus closed. In Pantarbes (Fig. 34) the two veins coa- 
lesce for the greater part of their length, and cell M} is com- 
pletely obliterated. 
The coalescence of veins Cuz and Ist A.— The second branch 
Fic. 36. — Wing of Scenopinus. 
of the cubitus and the first anal vein may also coalesce in vary- 
ing degrees. In Rhyphus (Fig. 29) these two veins retain 
their primitive position. In Leptis (Fig. 30) the tips are ap- 
M,+ Cu, 
Fic. 37. — Wing of Rhamphomyia. 
proximate. In Thereva (Fig. 32) the tips coalesce for a short 
distance. In Conops (Fig. 35) the coalescence is more strik- 
ing. In Scenopinus (Fig. 36) it is carried still farther. While 
