318 



penultimate, ventral segments; lateral abdominal spiracles indis- 

 tinguishable ; apical segment much elongated ; the apical 3 or 4 seg- 

 ments tapered posteriorly in Stratiomyia; posterior spiracular cham- 

 ber in apex of last segment, fringed with long soft hairs. 



Imago. — Third antennal joint without a differentiated arista; 

 abdomen with 5 or 6 visible segments ; 4 posterior veins in wing be- 

 tween apex of third vein and apex of second branch of cubitus, the 

 first cubital branch arising from the second basal cell. 



HABITS OF LARVAE 



The larvae are aquatic, their food consisting of algae, decaying 

 vegetable matter, and minute organisms such as crustaceans. 



HABITS OF IMAGINES 



The flies are invariably flower-frequenters, occurring in large 

 numbers on Umbelli ferae, etc. 



Key to Genera 



larvae and pup aria 



1. Apical abdominal segment very much elongated, more than 3 times 

 as long as its greatest width ; penultimate and antepenultimate 

 ventral segments without curved thorns; antennae about three 



times as long as their diameter Stratiomyia. 



— Apical abdominal segment at most 3 times as long as its basal width ; 

 penultimate and antepenultimate ventral segments, or only the 

 former, with 2 or 4 strong curved thorns on their posterior mar- 

 gins ; antennae about 6 times as long as their diameter 



Odontomyia. 



Stratiomyia Geoffroy 



GENERIC CHARACTERS 



Larva and Puparium (PI. XLVII, Fig. 1). — Elongate, slightly 

 Capering anteriorly; the head elongate, antennae short. Posteriorly 

 the body is usually much attenuated, the last segment being more 

 than 3 times as long as its greatest width ; no curved thorns on ven- 

 tral segments ; dorsum with or without surface hairs, but without the 

 well-defined transverse series of 6 bristles so noticeable in Geosarginae 

 and Pachygasterinae, and without curved thorns on posterior margin 

 of antepenultimate and penultimate segments ventrally. 



