408 C. H. TURNER 



the data will prove of interest. The authors' description of the 

 nest-building of Odynerus annulatus Say is intensely interesting. 

 In digging its nest this species moistens the soil with water, 

 removes a small portion of the moistened soil and with it begins 

 to construct a turret around the spot. Some more water is 

 added and another small portion of the soil is removed and 

 added to the turret. This is repeated over and over again and 

 the turret, which is smooth on the inside and rough on the 

 outside, grows apace. As the work advances only a part of the 

 pellets removed from the burrow are built into the turret. The 

 others are carried a distance of from four to six feet and dropped. 

 Whence comes the water to moisten the soil? The wasp brings 

 it, in her mouth, from a nearby lagoon. These investigators 

 contribute additional proof, if such be needed, of the tool using 

 instinct of the Ammophilae. They found one species of Ammo- 

 phila using a stick to tamp the dirt, on its burrow and another 

 species using the tibia and tarsus of a small locust for the same 

 purpose. 



In his new book, Comstock (21) describes the webs, and in 

 some cases the web-making activities of a large number of 

 spiders, and, in a second contribution (20) he discusses, in the 

 following manner, the probable evolution of the spider web. 

 Some spiders in constructing their webs use several distinct kinds 

 of silk, for the elaboration of which complicated spinning organs 

 have been evolved. At least seven different kinds of silk are 

 spun by spiders. From the few silken strands used by Pholcus 

 to fasten her eggs together to the dense sheets used by others 

 to construct elaborate egg-cases, silk in some form is used by 

 all spiders in caring for their' eggs. This was probably the 

 primitive use of silk. Spiders living in burrows strengthen them 

 by means of silk; some construct silken covers for the burrow 

 and others build silken turrets. The most important step 

 towards real web building was acquiring the habit of spinning 

 a drag-line. 'The step from drag-line to web is not a great one. 

 A spider spinning a thread wherever it goes would make a web 

 it, by chance, it moved about in a limited space, as in some 

 nook in which it had taken up its abode. In such a web insects 

 would be trapped, and thus might arise the habit of building 

 webs for the purpose of trapping insects." The simplest webs 

 are irregular and constructed out of dry silk like that used for 



