1916.| B.SuNDARA Raj: Freshwater lish of Madras. 261 
habits clear water. Being a surface-feeder it is frequently seen 
near the surface of the water. 
“The chelas are remarkably active in the early mornings and evenings, which 
means that they are thoroughly on the feed then. During the middle of the day 
they seem to favour the deeper waters and become less active, occasional rises 
being seen in the centre or deep parts of the pool, but not feeding regularly.” ! 
In sport or when chased they shoot into the air; more fre- 
quently they expose their silvery sides at the surface of the water 
in bright sunshine. 
Uses.—This species attains a maximum length of six inches 
and is esteemed as food. The doubt cast on the usefulness of 
species of Chela in destroying mosquitoes by some writers” has been 
criticised by Mr. H.C. Wilson.2 My own experiments show that 
C. clupeoides readily eats mosquito larvae at any rate in captivity. 
Possibly C. argentea differs from the present species in this respect. 
Perilampus cachius (H. B.) 
(P. atpur of the Fauna of British India.) 
Tanul—Salvaz. 
Cachius being the first of the two specific names (cachius and 
atpar), used for this species by Hamilton-Buchanan‘*, has to be 
adopted according to the law of priority. 
In Madras specimens the anal fin has only 20 to 22 rays, the 
number of longitudinal rows of scales between the L. line and the 
base of the ventral fin is frequently only 34, and the number of 
perforated scales on the L. line usually only 50. I have not seen 
this species more than an inch anda half in length, though it is 
said to grow to a maximum length of 4 inches. 
It is a rare fish in Madras. I have met with it very occa- 
sionally in the Cooum river and in the Sembarambakkam tank. 
Uses.-—Messts. Sewell and Chaudhuri mention it as a mos- 
quito-destroyer.° 
Lepidocephalichthys thermalis (C. and V.) 
Tamil—A saraz. 
This common species abounds in the rivers where the bottom 
is sandy, and in ponds. 
Habits.—L. thermalis inhabits the bottom mud or sand of 
tivers and ponds, where it usually lies buried during the day, 
venturing out to feed at night.’ The burrowing in mud or sand 
does not appear to be a laborious process. In an aquarium, when 

1 Wilson, Some notes on larvicides and natural enemies of Mosquitoes in 
South India. Proceedings Third General Malaria Committee, Madras (Novem- 
ber 18th, 19th and 20th, 1912). 
2 Bentley, 27d Rev. Wellcome Laboratory, p. 418; Sewell and Chaudhuri, 
Ind. Fish of Proved Utility as Mosquito-destroyers, p. 19. 
SEN Cy Wiser. foie. 
+ Hamilton-Buchanan, Fishes of the Ganges, pp. 258 and 259. 
5 Ind. Fish of Proved Utility as Mosquito-destroyers, p. 19. 
