Mr Lamb, Venational Abnormalities in the Diptera 395 



The second class consists in an extra cross-vein between the 

 third and the fourth long veins as shown in Fig. 5, Sapromyza 

 pallidicornis (Sapromyzidae), Fig. 6, Minettia plumicorms{Sa.pTomj- 



Fig. 1. Platypeza dorsalis 



Fig. 3. Ocydromia glabricula. 



Fig. 2. Osrinis nana. 



Fig. 4. Agromyza sp. 



Fig. .5. Sapromyza pallidicornis. Fig. 6. Sapromyza plumicornis. 



Fig. 8. Orthochile nigrocerulea. 



Fig. 7. Ditaenia grisescens. 



zidae) and Fig. 7, Ditaenia grisescens (Sciomyzidae). The only known 

 case in which the cross-vein at the end of the discal cell is duplicated 

 shown in Fig. 8, Orthochile nigrocerulea (DoHchopodidae). 



IS 



