Setihercostomus Zhang et Yang, 2005 is separated from the genus Hercostomus Loew, 1857, by the following combination of characters: clypeus short and narrow, not reaching lower margin of eyes, bearing one pair of strong bristles in both sexes; pteropleuron (= anepimeron) with group of fine hairs in front of posterior spiracle; male cercus large and thick, nearly as long as epandrium (Zhang & Ya...

Two new species Medetera sakhalinensis Negrobov & Naglis sp. nov. from Russian Far East (Sakhalin) and M. emeljanovi Negrobov & Naglis sp. nov. from Mongolia are described and differential diagnosis are given.

The fly Hydrophorus alboflorens (4 mm long, 4.7 mg mass) moves around upon and jumps from water without its tarsi penetrating the surface. All six tarsi have a surface area of 1.3 mm(-2) in contact with the water, but they did not dimple its surface when standing. Jumping was propelled by depression of the trochantera of both hind and middle legs, which are 40% longer than the front legs and 17...