1917] The Ottawa Naturalist. 105 



suspect that this variation has to do with the pairing of the sexes and 

 that females do not commence to burrow until after they have become 

 fertilized. The mature males, of course, die before winter sets in. 



On September 16, 36 adult burrows of L. missouriensis were 

 measured and were found to have attained an average depth of 3 feet 

 1 inch, the deepest being 5 feet 3 inches and the shallowest 1 foot 4 

 inches. The deeper burrows had not been further extended for some 

 days, while the spiders were busily at work with the shallower ones. 

 By October 1 , many holes had been closed and a measurement of 9 of 

 these indicated an average depth of 3 feet 9 inches. 17 holes still 

 open, but showing no recent signs of digging, averaged 4 feet 1 inch 

 in depth. 15 holes in which the spiders were still digging showed an 

 average depth of 3 feet 7 inches. The deepest closed hole was. 4 feet 

 5 inches, the deepest open one 4 feet 10 inches. Closed holes are 

 thoroughly covered in with grass, leaves and sand fastened together 

 with web in such a way as to make them practically water tight. It 

 was observed that the earliest closed burrows were always in shady 

 situations which would indicate that the shadow had induced an 

 earlier closing than in the case of those exposed to the sun. Burrows 

 in low, wet, lands are shallower than those on the higher lands. 33% 

 of the spiders were still digging on the above mentioned date. 



On October 5, about 22% of the adults had closed their holes 

 though all the young were still digging. 



On October 8, cold weather seemed to have induced a closing of 

 nearly all burrows, only a few of the smaller ones remaining open. 

 20 adult holes on high land had an average depth of 5 feet 1 inch, the 

 deepest being 5 feet 8 inches and the shallowest 4 feet 4 inches. 

 Measurement of young spider burrows indicated an approximate depth 

 similar to those of adults. 



On November 5, a mature individual was dug out at 4 feet 7 

 inches. This burrow though perpendicular in direction, had numerous 

 small curves, due to the spider having encountered obstacles in 

 digging. For the first 3 feet this hole was rather densely lined with 

 web but became less so towards the bottom. It had also been stopped 

 with sand at several places, the sand being held in place by web. This 

 spider was found, at the bottom of her burrow slightly sluggish but 

 with sufficient energy to defend herself. A young example provided 

 a similar burrow but slightly deeper. It was stopped at two places. 

 The ground at this time had been frozen to a depth of four inches for 

 some days but at the time of observation was thawed out. These two 

 individuals were placed in the warm sun and became quite active; 

 they refused, however, to dig a new burrow and had moved but little 

 by the next day. 



As L. wrightii was not found in such close vicinity it did not 

 receive the careful attention given to L. missouriensis. Judging from 



