204 AGRICULTURAL EXPERIMENT STATION. 



out ; not for a day or a week, but for months ; hatching promptly 

 as soon as they became water covered. 



Nevertheless, though it was now possible to appreciate the 

 conditions under which the species became at times so horribly 

 abundant, there were several points of practical interest that 

 were left undetermined. For this reason, in 1903, I assigned 

 Mr. Viereck to the Cape ]\Iay station, where opportunities for 

 study were abundant, and the following series of experiments 

 brings out in relief those peculiarities that were only guessed at 

 before. 



MR. VIERECk's experiments. 



July 24th, placed one dozen gravid females into each one of 

 two Cjuart jars, in which the bottom was thinly covered with 

 marsh sod. July 25th, some were dead, and only three females 

 had the abdomen yet distended. July 27th, only three living 

 specimens remained and in these the abdomen was collapsed. 

 July 28th, all w-ere dead. July 30th, the sod was examined and 

 black eggs were found, most of which must have been laid during 

 the night of July 24th. "The eggs were evidently white when 

 laid and became black subsecjuently." It rained during the night 

 of July 29th, and water covered the bottom of one of the jars in 

 which baby wrigglers were found on the 30th. These lived un- 

 til August 5th. when only a few survived. On the 6th, a new- 

 lot of babies hatched and some sound eggs yet remained in the 

 sod. Only a few' eggs in this series collapsed. 



August 2d, prepared two one-cjuart jars with moist lint at the 

 bottom and two others with lint covered with moist marsh mud, 

 which had been sterilized to make certain no hve eggs were in- 

 troduced. Ten gravid females were placed in each and oviposi- 

 tion began while the jars w-ere yet under observation. One speci- 

 men extended its ovipositor, darted its end into the sod until it 

 found a suitable place, then laid six eggs, one after the other, and 

 flew off. Another placed fifty-two eggs, one by one, in an ir- 

 regular row about an inch long, in one continuous laying. A 

 third took great pains hunting up a suitable place by darting its 

 ovipositor in many directions before placing each egg. At 6 

 P. M., and a few minutes after, an injured female laid all its eggs 

 in a heap, one by one. but rapidly. At 7.30 P. M., those first laid 

 were black, the rest assuming a gray color and becoming black 

 from the end first laid to the end last to appear. Some of the 

 eggs were placed and kept in a dark place, but these blackened 

 as rapidly as did those kept in the light. Eggs taken from the 



