THOCEEDINGS OF THE THIRD ENTOMOLOGICAL MEETING 683 



did not yield its tenant which in some cases most probably happened 

 to be beyond the arm's length of the children. On an average one 

 crab was obtained from one hole in every three. Sixty crabs in 

 different stages of growth were thus collected in a very short time. In 

 all about 80 crabs were obtained. They comprised the following three 

 different species as determined in the Indian Museum, Calcutta, after- 

 wards : — 



(1) Potamon {Acanthopotamon) martensi, Wood-I 



(2) Paratelphusa (Parafelphusa) spinigera, Wood- 



(3) Potamon (Acanthopotamon) sp. nov. allied to P. (A.) wood- 



masoni, Alcock. 



The majority of them were P. (A.) martensi. P. (P.) spinigera was 

 fewer in number. While there were only a few specimens, probably 

 only one, of the new species of Potamon which happened to be sent 

 to the Indian Museum for identification. At the time they were 

 collected no attempt was made at discrimination and they were kept 

 together in the following manner in a shed in the Insectary compound 

 in two zinc cylinders. About six inches of earth was placed in the 

 cylinders and stools of rice plants about three-fourths grown trans- 

 planted mto it and then water was poured in so that it stood about 

 two inches above the level of the earth. In one cylinder two feet in 

 diameter fifteen crabs were put in with ten stools havmg 49 plants. 

 In another cyhnder three feet in diameter 55 were kept with 80 plants 

 in 1 7 stools. They seemed to be at ease in both the cylinders. Between 

 26th October and 15th December only five plants in the smaller cylinder 

 and 6 plants in the larger, were cut and none afterwards. No part 

 of the cut plants was observed to be eaten. The crabs lived in these 

 cylinders up to June 1918. All did not live, many dying at intervals. 

 Thus at the end of April 1918 only three in the larger cylinder were 

 alive and none in the smaller. They did not breed and were not observed 

 to be dormant at any time. There was no food unless of course they 

 derived anything from the mud and water. Mosquitos were breeding 

 in the water but there was nothing to show that the crabs were preying 

 upon the mosquito larvse. Probably they did not require any food 

 as they are knoum to hibernate and sestivate underground from about 

 December to June under natural conditions. 



On the 13th April 1918 a second visit was paid to the same locality 

 at Munni where the crabs were collected in October 1917. The 

 fields were perfectly dry at this time. A search was made for crabs 

 in two reservoirs of water and they could be found in holes near the 

 edge of the water but their number was by no means large. Several 

 boys took several hours to collect 30 only. Those collected were in 



