,U^"s- 



AGKOMYZTDiE. 103 



hngituilinal vein; diseal cell sometimes confluent with the 

 ""^iiiwial cell (Cri/j}tnch(Hu))/, Aulacigaster), posterior cross-vein 

 sometimes wanting {Phytoviyza) ; anal cell present; cross-veins 

 often much approximated (Agromyzinffi). 



This family of small or minute flies, as here defined, includes 

 the Agromyzinse, Milichinse and Octhi])hilince of Schiner, the 

 Agromyzida? and Fhytomyzidse of Loew. The grouj) is 

 somewhat difiicult to define in such a way that the novice will 

 always feel sure of his determinations. From the Drosophi- 

 lidie (or at least the known American species) it will be dis- 

 tinguished by the non-plumose arista. From the Ephydridte, 

 Aulueigaster and Cri/ptocha'tum will be distinguished by the 

 presence of a distinct anal cell. From the Geoniyzidae it is 

 difficult to distinguish some of the genera, especially of the 

 Milichinte and Ochthiphiliufe. The student would best con- 

 sult the table of that family in cases of doubt. Bhicnoe'ssa 

 Loew is not included in the table : I can not define it. 

 ^ The larvae of Phytomijza are usually leaf miners. The lar- 



' vae^ of Leucopls feed upon plant-lice; those of Ochthvphila 

 have been found in tlie galls of Tritlcv/ni repens. Tlie larvae 

 of Agromyza are elliptical in shape, the hind stigmata situated 

 upon small, rounded plates on the under side of the last seg- 

 ment ; the abdomen is provided with false legs, without 

 bristles. The larvge of Leucopls are cylindrical, thicker pos- 

 teriorly, the skin roughened with short hairs ; hind stigmata 

 elongate, tube-like and widely separated; they creep leech- 

 like, or like the geometrid larvas. 



TABLE OF GENERA. 



1. Posterior cross-vein absent; oral vibrissa- present (Phytomyzlinr). 



PiiYTOMYZA Fallen. 

 Posterior cross-vein present. ........ 2 



2. Posterior cross-vein situated before the middle of the winp, tlic two 



cross-veins approximated. .8 



Posterior cross-vein at or beyond the middle of the wiiiff, the two eross- 

 veins not approximated ; arista liare. ..... 7 



