JASSIDS. 
735 
of other species are commonly seen on their food-plants. Idiocerus has 
a curious cycle, as there is but one brood yearly on mango in the early 
hot weather and the imago lives over on the tree for the rest of the 
year. It is possible that this occurs also in many other species, and it is 
probable that there is a very close inverse relation between the 
vigour of the host plant and the prosperity of the Jassid species. 
Hibernation appears to occur usually in the imago stage, but there is 
very little accurate information on this point. Equally little is known 
of the parasites or enemies of this family. 
These insects are found commonly in grass, low vegetation, on the 
soil, more rarely on trees ; their food-plants are little known ; Idiocerus 
is found on the mango tree and other species specially feed upon rice, 
cotton, etc. They are of little economic importance, the species 
attacking mango destroying the blossom, the species attacking 
cotton causing a curling of the leaf of the broader-leaved varieties 
(American and tree cottons), as does the species attacking Castor; 
as with other small sucking insects, there is a marked relation between 
the vigour of the host plant and the amount of Jassids attacking it, 
and it has been often observed that weak plants are more infested 
than vigorous ones (see Indian Insect Pests, page 109). The number 
of Jassids in pasture is sometimes enormous, and it is possible that 
injury is caused in such cases, though we are not aware that it has 
ever been proved. 
Distant has recently described the Indian forms in Volume IV of 
the Fauna of India ; we are aware of no published information on this 
family except descriptions of species, which are all referred to by 
Distant. Large numbers of species probably remain to be described 
since the plains fauna especially has been little collected and it is very 
extensive, probably equal to the sub-tropical fauna. 
Distant enumerates 340 species in the 
Fauna of India, Vol. IV, of which 54 are 
actually recorded from localities in tropical 
India, chiefly from the Pusa collection. 
Ledrince .—A small number of species 
of very marked facies, the broad foliaceous 
head specially distinguishing our species. 
Fig. 510— Ledra mutica. 
x 14. 
