324 AGRICULTURAL EXPERDIEXT STATION. 



other than the spring-s, nearly or quite all of which had a greater 

 or smaller supply. The chief point of interest was a stretch of 

 swampy bog land that had been burnt over early in 1902, the 

 fire eating through the moss in places and leaving a mass of ir- 

 regular holes, var^^ng in size and depth. Some of these were 

 partly closed bv vegetation covering in from the edges and 

 making an overhang'. The gTound was springy and there were 

 numerous springs round the edp-es. so that the water was alwavs 

 cold and usually clear ; but witli ^ flocculent sediment which was 

 readily stirred up. 



January 9, 1903, with the thermometer 9 degrees above zero, 

 the entire swamp was frozen solid. Januar}^ 23d broke the ice 

 on likely pools and made about a dozen dips in as many places. 

 Nothing was found and the inference is that the insects shelter 

 eitlier in the mud or under the overhanging ^-egetation. Janu- 

 ary 30th, during a mild spell, collections were made in pools 

 from which the ice had just disappeared, and now quite a little 

 series of specimens was obtained, some of them inactive and 

 apparently dead, but all revived when brought indoors. On the 

 31st, covered another part of the same territor}- and found speci- 

 mens everywhere : "Little holes, not over two inches in diameter, 

 full of water, turned out two or three specimens." February ist, 

 collected additional specimens and brought in some of the ice 

 to see whether larvse were frozen in it. Found that there were 

 none and that the specimens probablv kept down below actual 

 frost, if possible. Februar}^ 7th, it was noted that there was con- 

 siderable difference between the lar\-se, as though two or more 

 stages were represented, and, as a whole, they were more ad- 

 vanced than in December; in the larger specimens a distinct 

 shield-like fonn of the thorax was now apparent. Collections 

 were made throughout February, and the indoor cultures were 

 under constant observation; but though the larvae seemed to 

 feed continually they did not grow and spent most of the time at 

 the bottom of the jars: they do not need air from above the 

 surface. On Februar}'- 22d, when the ground was snow covered 

 and everything frozen over, holes were made in the ice and active 

 larvse were dipped up from beneath it. The water here was 36 

 degrees, and in the woodland springs where other specimens 

 were taken it ran 42 degrees. Rain and snow so filled the swamp 

 area that the wrigglers were scattered over so large a territory 

 it was almost impossible to find them. At this time a series of 

 the specimens was sent to me to be developed in the laboratory, 

 and these arrived in good condition. Throughout March col- 

 lections were made, and during this time it became so dry that 

 it seemed as if all the lar\-ae must have perished : yet after a 



