ELISHA MITCHELL SCIENTIFIC SOCIETY. 33 



tube with slanting door. Fig. 4, trench with wall each side seen from one 

 end. Fig. 5, arch. connecting walls. Fig 6, same, closed at one end. Fig. 

 7, same, with trap-door built «t the other end. Fig 8, another built on 

 same plan, but the first opening n'»t quite closed, a loose flap at a. Fig. 



9, tube dug between two walls, hiage at <f, distal part of door at h. Fig. 



10, curved tube with door hung so as to swing to the right and left. Fig. 



11, section of bottle showing work of spider : a, wall, b, pellets of earth 

 earned up and stuck to the glass, c, n^-st, a tower against the side of the 

 bottle. Fig. 12, nest showing concentric "lines of growth," in the trap- 

 door. Fig 13, h, first hole dug by spider, c, second one, d, wall between 

 which was r moved making of the excavation a trench, subsequently d, 

 was rest red and nest built in normal way at h. Fig. 14, spiders repre- 

 sented in act of spinning silUen lining to the upper end of the tube. Figs. 

 15 and 16 P. turris adult spider taking a novel method of excavating a 

 hole 



Note. — The doors of all the young trap-door spiders' nests are very 

 thin, from 2 to 3 °"^. in thickness. One spider worked so rapidly tliat it 

 would sometimes pick up and unload a pellet of earth in 8 seconds. As a 

 rule they required a much longer time than this. 



DESCRIPTIONS OF SOME NEW TRAP-DOOR 

 SPIDERS; THEIR NESTS AND FOOD HABITS. 



A few months after writing the previous article, "A new 

 trap-door spider," I found a specimen which differed so 

 markedly in color from the one, the subject of that article, 

 and agreed so closely with the one described by Hentz as 

 Mycfih' cnrolinensis,' now Paclnjlnmomis cfrroh'jK'ih'sis^' Hentz, 

 that before having an opportunity to study them carefully I 

 concluded the only difference was in color. Just after the 

 article "A family of young trap-door spiders," w^as ready, I 

 discovered that the two forms were different species ; that' 

 the one called *'A new trap-door spider,', and the young 

 spiders whose work has just been described in the Ento. 

 Am. were both new species : the former I have called 

 Pachylo merits carahivoruSy and the latter Pachjjlonierus 

 Ai-sjnnoHUs. 



The nests of P, cnruhivorus^ P. ^-spinosus, have already 



^The Spiders .'fthp United States, by Nicholas Marcv llus H<-ntz M. 

 D, Boston Journnl, IV; p. 56, pi. VIl, fig. 3. 

 ■^Beitra.g€ zur Kenniniss der Teiritelariae, Ausserer, p. 147. 



