1918] 



The Ottawa Naturalist 

 COLLECTING NOTES FOR NORTHERN SPIDERS. 



13 



By J. H. Emerton. 



The most conspicuous northern spiders are the 

 Lycosidae, which run on the ground and catch in- 

 sects for food, without the use of cobwebs, taking 

 shelter, especially in breeding time, in holes in the 

 ground, or among plants, which they line more or 

 less with silk. Some species, known to live as fat 

 north as Ontario and Manitoba, dig holes in sandy 

 soil, and these may live farther north and should 

 be looked for wherever there is sand only partly 

 covered with plants. The hole usually has a per- 

 fectly round opening thickly lined with silk, to 

 which sometimes sand and bits of straw are at- 

 tached. 



All spiders eat insects, but, as far as known, any 

 spider may eat any insect which it can catch. All 

 observations on choice of food by spiders would be 

 useful, for instance, whether L^cosidae would catch 

 Lepidoptera if the latter came their way. 



The Lycosidae carry their eggs in a round silk 

 bag attached behind to the spinnerets, and the 

 young, after leaving the bag, hold for some time 

 to the mother's back. The young hatch in mid- 

 summer and become half grown before winter, 

 when they take what shelter they can find near the 

 ground and remain torpid until the next spring, 

 when they grow rapidly, maturing in June, the 

 males before the females. The pairing takes place 

 as soon as the females are adult, and this is the best 

 time to collect them to be certain which males and 

 females belong together. Many of these species 

 are very variable and there is much doubt about 

 their classification. 



The distribution of many L^cosidae is extensive; 

 for instance, Pardosa glacialis extends all over 

 North America as far south as New York and 

 Ohioward. L^cosa plctilis, under various names, 

 extends along the Arctic coast from Siberia to 

 Greenland, and south to Labrador, the White 

 Mountains, Norway and the Alps. Specimens are 

 desirable from as many places as possible. 



Next to the Lycosidae, the most conspicuous 

 spiders of the north are the very small species of 

 Erigone and its allies, which live in enormous num- 

 bers close to the ground in small flat cobwebs which 

 become visible only when covered with dew. These 

 spiders are most readily found under stones and 

 sticks lying on the ground. They also live in dead 

 grass and litter of all kinds along the seashore and 

 banks of ponds and rivers, and in the moss and 

 decaying leaves that collect under trees and bushes. 

 This loose material should be shaken and sifted on 



a large cloth, blanket or tarpaulin, the coarser 

 parts thrown off and the dust carefully examined. 

 I use a waterproof cloth three feet by six, and on 

 this place an armful of litter, taking care to get the 

 portion nearest the ground. This is beaten and 

 shaken for a few minutes and the larger part taken 

 away. The rest is shaken to the middle of the cloth 

 and sifted in a sieve of three wires to an inch, which 

 removes most of the straw, leaves and moss, and lets 

 through the dust, insects, spiders, etc. Everything 

 alive soon shows itself by movements as the various 

 species recover from the shaking and become warm 

 in the sun. 



Epeira carbonaria, which makes round webs be- 

 tween bare stones in the Rocky Mountains, Labrador 

 and the Alps, has not been reported from the Arctic 

 coast, but should be looked for there on rock- 

 covered hillsides above the shore. The spider is 

 gray, like dark granite. It hangs in the middle of 

 the web and drops at the slightest jar, but soon 

 returns. Any cobweb should be watched in the 

 evening, when the spider is more likely to expose 

 itself. At other times the spider may be found in 

 a nest at one side of, or above, the web. 



A large number of spiders inhabit the spruce 

 forest and extend across the continent. Many of 

 these are found as far north as Hudson Bay and 

 Alaska, but their northern limits are unknown. The 

 most northern trees should be examined by beating 

 them over a cloth laid on the ground well under 

 the branches, and the falling animals picked from 

 the cloth. Some of the tree spiders make large and 

 conspicuous cobwebs and these should be examined 

 in the morning when covered with dew, and, if 

 possible, photographed then within an hour of sun- 

 rise. 



Sphagnum does not usually shelter many spiders, 

 but the moss which grows undet trees and on de- 

 caying wood often contains many. 



The leaves under birch and willow trees should 

 be sifted, even if in small quantities. 



It is expected that the new Field Museum, 

 Chicago, for which ground was broken in the sum- 

 mer of 1915, will be ready for the transfer of the 

 contents of the old museum in Jackson Park by 

 August, 1919. The new building is situated south 

 of Twelfth Street and east of the Illinois Central 

 Station. It is of Georgia marble, and, exclusive of 

 the porticoes, will measure 756 feet long and 350 

 feet wide. It will cost $5,000,000. 



