PELOGONIDJS. 
709 
CRYPTOCERATA. 
This division includes the truly aquatic forms, as distinct from the 
land forms and those living on the surface of water. Apart from the mere 
enumeration of species, practically nothing has been done to investigate 
these insects, and there is a very large field open to an investigator in 
almost any part of the plains. They have probably no economic 
importance whatever, and the study of these insects even in Europe and 
the United States is very little advanced. 
Pelogonim;. — (Galgulidce). 
Body short and broad ; head very broad with prominent eyes ; ocelli 
present. Posterior legs thin, formed for running. 
A family containing but four recorded species in India, one at least 
of which is probably very widely spread over the plains. These insects 
are of small to moderate size, the body broad 
and flat, the head broad with prominent eyes, 
the posterior legs not formed for swimming, but 
for running or leaping. Pelogonus marginatus, 
Latr., has been found on the mud on the banks of 
streams ; it is an active little insect of a dull colour, 
with small ochreous spots; when approached it 
leaps vigorously, alighting some distance off and 
lying flat on the mud. It is most readily captured 
by being chased to the water when it leaps in, and 
is for the moment helpless. Mononyx includes 
rather larger insects of a rather brownish 
colour and roughened above ; the forelegs are raptorial, the femur 
dilated, the tarsus single jointed. Three species are recorded from 
Burmah, Sikhim and Assam ; more remain to be captured probably. 
Nothing appears to be on record as to the habits of these insects ; 
Mononyx indicus, Atk., is not uncommon in Assam and Sikhim, where 
it is found on grass paths, on the soil and under stones, as well as on 
hard roads; it is not aquatic and is possibly predaceous on small 
insects. 
Pelogonus marginatus, Latr., has been observed to suck a helpless 
insect on the surface of the stream near the margin and the structure of 
the legs of Mononyx would indicate that it has somewhat similar habits. 
Fig. 481.— Pelogonus 
MARGINATUS. X 5. 
