382 INSECT TRANSFORMATIONS. 



swimming against small streams, and apparently 

 more for the purpose of maintaining their place than 

 of making farther progress upwards. The most 

 common of these are two aquatic bugs of different 

 genera — the one (Gerris locustris, Latr.), with a 

 long blackish body and legs, and white belly, though 

 more clumsy in form than the water-measurer {Hij- 

 drometra stagnorumj formerly mentioned ; and the 

 other (^Velia currens, Latr.), with short body and 

 feet, black, with a red line running along each side. 

 We have been still more amused with a dark greenish- 

 grey spider {Lycosa saccata, Latr,), which, when we 

 approach near its haunts on the margin of a stream, 

 does not take shelter in the grass, nor in the holes of 

 the bank, as most of its kindred would do, but trips 

 away over the water, where it appears to know in- 

 stinctively that we cannot so easily pursue it. Tliis is 

 not, however, the diving water-spider {Argyroneta 

 aquaticd)^ for though it can dive and remain under 

 water, it does not seem to relish this, except when 

 driven to the measure.* 



h, Hydrometra stagnorum. c, d, Hydrachna Geograpkica, Latb., 

 front and back view, both magnified, e, Velia rivulorum, Latr. 



