146 THE AMERICAN MIDLAND NATURALIST 



made, have not been recorded in the literature on the subject to 

 which I have had access. 



The food of M. Aurantia consists chiefly of insects. But 

 spiders will eat other spiders, and, after the pairing season, the 

 female usually devours the male. In September, 1917, a male 

 and female were brought to the writer's laboratory. The collector 

 had put them into a pill box. When the box was opened, the male 

 was found tightly wrapped in his shroud, and the female had 

 already begun her meal. The staple article of food of M. Aurantia 

 seems to be grasshoppers. These are swathed in a wide band of 

 silk and then rendered palatable by the injection of some venom 

 through a bite with the spider's chelicerae. Other insects of many 

 species are devoured with avidity, even such large species as dragon 

 flies and butterflies. The following is a list of insect remains 

 found in the webs of this species during the months of August and 

 September, 19 16 and 191 7: Libellula basalts, Libellula pulchella, 

 Argia violacea, Annosia plexippus, Helophilus latifrons, Euschistus 

 variolarius, Sympetrum rubicundum, Mesothemis simplicicollis, 

 katydids and weevils. 



The process of swathing a captured insect is interesting. To 

 observe this at close range, one has but to introduce a grasshopper 

 into the web of a mature female. The spider will rush at the 

 grasshopper, pierce it with the chelicerae and then dart off to safety. 

 After a brief wait, the spider will approach the insect and, pulling 

 out a sheet of silk from its spinnerets, with one hind leg, thrust the 

 sheet against the grasshopper. In doing this, the spider uses first 

 one hind leg and then the other, whirling the grasshopper around 

 rapidly. The captive is thus securely wrapped in a tight band of 

 silk composed of many parallel threads, and is immediately de- 

 voured or left for a more opportune time. 



The task of spinning the web is begun by throwing out a 

 thread which is carried by the air till it strikes some object and 

 adheres to it. This line is now pulled tight and forms a kind of 

 bridge over which the spider may travel. Foundation lines are 

 now thrown out and these are connected by radii. The center where 

 these radii converge is strengthened by a mesh or net-work of lines, 

 called a hub. A characteristic structure of the web of Aurantia is 

 the stabilimentum. This is a zig-zag ribbon across the center, 

 or below the hub. It consists of a large number of minute threads 



