168 HTDllOMETRIDiE. 



Family HYDROMETRID^. 



This family may be distiuguished from the Hebridse by the 

 four-jointed antennae, while, as in that family, the abdomen beneath 

 is clothed with a silvery velvety pubescence. These insects are 

 all aquatic or subaquatic. Some very distinct genera are included 

 in the Hydrometridte, which give to this group a heterogeneous 

 appearance ; but the family is still — as is shown particularly by 

 the life and habits of the species — a natural one. It is divided 

 into four subfamilies, all of which are represented in British 

 India. 



Champion (Biol. Centr.-Amer., Rhynch. ii, p. 123) has included 

 Mesovelia in the Hebridse, as had formerly Dr. Puton ; but such a 

 position for the genus is not genei'all)' accepted and is not 

 followed here. 



Synopsis of Subfamilies *. 



A. Coxae contiguous or nearly so ; scutellum 



visible Mesoveliince. 



B. Coxaj widely separated, scutellum covered. 



a. Head very elongate in front of eyes, many 



times longer than wide Hydrometrina'. 



b. Head short, as wide across the eyes as 



long. 



a. Posterior femora not extending to the 



abdominal a]:)ex VeUince. 



b. Posterior femora long and slender, ex- 



tending far beyond the abdominal 



apex Gerrince. 



Subfamily I. MESOVELIIN^. 



This subfamily is represented by a single genus, and is some- 

 what generally distributed, but not yet recorded from the 

 Ethiopian Eegion. According to 8ahlberg, Mesovelia frequents 

 the leaves of Nymplum, Fotainorjeton, &c. 



Genus MESOVELIA. 



Mesovelia, Muls. S,- Hey, Ann. Hoc. Linn. Ltfon, 185:2, p. 138; 



Fieber, Eur. Hem. pp. 33 & 105 (1861) ; Sahib. Not. Fuun.Wl. 



Fenn. xiv, p. 259 (1875) ; Saund. Hem. Het. Brit. Islds. p. 145 



(1892). 

 Fieberia, Jakoid. Hor. Soc. Enf. Boss, vii, p. 32 (1873). 



Type, M. furcata, Muls. & Eey, a Palsearctic species. 



* I have here very largely followed the synoptical characters so clearly 

 given by E. Saunders (Hem. Het. Brit. Islds. p. 144, 1892). 



