163 



of vegetation. This species has received considerable study. 

 McCook ('90) and Porter ('06) record many observations on this 

 species. Howard ('92b) has discussed its hymenopterous parasites 

 and those of some other spiders. 



No specimens of Argiopc traiisz'crsa Emerton, the transversely 

 black-and-yellow^-banded relative of aiirantia, were observed at 

 Charleston, although they are fairly abundant in colonies of prairie 

 vegetation near Urbana, e. g. at Mayview, 111., Sept. 26, and on Nov. 

 26, 191 1. I have seen this species only among colonies of prairie 

 vegetation along railway rights-of-way. 



Thomisid.e 



Misumciia alcatoria Hentz. Ambush Spider. 



This crab-like flower spider was abundant upon flowers : on the 

 mountain mint, Pycnanthemiim flexiwsum (Sta. l,g), Aug. 8 (No. 

 6) ; on the mint, (Sta. I) with a giant bee-fly, Exoprosopa fasciata 

 Macq., Aug. 12 (No. 31); on the Loxa prairie (Sta. II) with the 

 same kind of fly, Aug. 13 (No. 47) ; on the prairie (Sta. I, g) on the 

 flower of the swamp milkweed, Asdcpias incarnata, Aug. 24 (No. 

 157) with a male bumblebee, Bonibus separatus Cress.; on Andropo- 

 gon (Sta. I, g) with a large immature female of ConocepJialiis, Aug. 

 24 (No. 1159) ; on the Loxa prairie (Sta. II) on flowers of Bryn- 

 giuni yiicci folium, Aug. 27 (No. 178) ; in the colony of Blymiis 

 (Sta. I, a) Aug. 28 (No. 179) ; and in the open glade of the low- 

 land Bates woods (Sta. IV, c) on the flowers of Bnpatoriuui avlcs- 

 tinum, with a very large syrphid fly, Milesia ornata Fabr. {=virgin- 

 iensis Drury), Aug. 26 (No. 184). These insects captured by the 

 spiders vary from about five to ten times the size of their captor. There 

 is considerable variation of color in this series of spiders. 



It would be well worth while for some one to make a special 

 study of this spider, and give us an account of its methods of cap- 

 turing food and finding fresh flowers, with a full account of its life 

 history. McCook ('90, Vol. 2, pp. 367-369) gives some informa- 

 tion alDout the habits of an allied species of spider, but the account is 

 meager. Some observations on the breeding habits of this species 

 have been made by Montgomery ('09, p. 562); and Pearse ('11) 

 has recently published the results of an interesting study of the rela- 

 tion between the color of these spiders and the color of the flowers 

 they frequent. He conclud'^s thnt nitb' i^di tliis spider may change 

 its color slowly (from yellow to white), it does not do so witli 

 rapidity or in such a way as to match its surroundings, and, further, 

 that it does not seek an environment or a flower colored like itself. 



