214 



AMERICAN SPIDERS AND THEIR SPINNINGWORK. 



CEPHALOTHORAX : Corselet irregular oval, truncated behind ; the median fosse deep, 

 cephalic suture well marked; corselet grooves distinct; color yellowish brown, with a yellow 

 marginal band; in some specimens lighter streaks of yellow mark corselet grooves and 

 caput; skin glossy and slightly pubescent; head on a level with or slightly above the 

 corselet; color yellowish brown, uniform with corselet and mandibles. The sternum is 

 shield shaped, about as wide as long; blackish or dark brown, slightly pubescent; skin 

 hard and glossy ; labium subtriangular, colored like the sternum ; the maxillae wide as long, 

 and rounded at the tip. 



EYES: Ocular quad on a black prominence; narrower in front than behind, sides 

 slightly longer than rear; the eyes are set on black rings; MR slightly larger than MF; 

 MF separated by about 1.5, MR by one diameter; side eyes on tubercles, not very pro- 

 nounced ; propinquate ; SF somewhat larger than SR. The clypeus height about two 

 diameters MF; front eye row well recurved, the longer rear row slightly procurved or 

 aligned. 



LEGS : 4, 1, 2, 3 ; yellow, with slight brown apical annul! ; armed with bristles and 

 short bristlelike spines, and are rugose, particularly upon the femora; palps colored and 

 armed as the legs. 



ABDOMEN : Somewhat an irregular oval, wider behind than in front, widest in the middle ; 

 the posterior is armed at the dorsal edges with strong but not long spinal processes, and 

 immediately beneath these are similar but smaller processes. The color is yellow, with a 

 folium of blackish color, interrupted in the middle. Several curved rows of circular brown 

 spots cross the dorsum, modifying the color, some bowed to the front and some to the 

 rear; similar spots are on the sides and underneath. The dorsum is reticulated, and is 

 glossy and hard; the spinnerets are placed well underneath, the venter is yellow, the spin- 

 nerets brown, as well as the space surrounding the gills and epigynum. The epigynum 

 (Fig. 6 front view, 6b side view) shows anteriorly a brown chitinous atriolum and a scapus 

 bent and blunt at the tip. Underneath the scapus and dividing the postulse is what may 

 be called a secondary scapus, wide at the base and somewhat rounded at the tip. 



MALE : Figs. 7, 7a, 7b. The male does not differ widely from the female in coloring and 

 markings. The apex of the abdomen is rounded, and is destitute of spinal processes. Its 

 size is a little more than half that of the female, being 3 mm. long. 



DISTRIBUTION : The geographical distribution appears to correspond closely with that of 

 its congeners, A. gracile and A. sagittatum. It has been collected throughout the New 

 England States, in New York, Pennsylvania, Maryland, District of Columbia, Virginia, 

 North Carolina, Georgia. I have specimens from Ohio, and as far to the north and west 

 as Wisconsin. Its distribution west of the Mississippi has not been determined, and it is 

 probably limited by the Rocky Mountains. 



No. 69. Acrosoma sagittatum (WALCKENAER). 



Plate XXIII, Figs. 8, 9. 



1837. Plectana mgtitata, WALCKENAER 



1850. Epeira spinea, HENTZ 



1884. Acrosoma spinea, EMERTON . . 



1888. Acrosoma sagittata, McCooK . . 



1889. Acrosoma sagittatum, MARX . . 



Ins. Apt, ii., p. 174; ABBOT, G. S., No. 



J. B. S., vi., p. 21 ; Sp. U. S., p. 123, xiv., 9. 



N. E. Ep., p. 326, xxxviii., 5-8. 



Proceed. Acad. Nat. Sci., Phila., p. 5. 



Catalogue, p. 540. 



FEMALE : Total length, 9 mm. ; abdomen, 4.5 mm. long from base to apex at the 

 median line, 7 mm. long from base to tips of posterior spines; width, 4 mm.; cephalo- 

 thorax, 3 mm. long and 2 mm. wide. 



CEPHALOTHORAX : A long oval, rounded, slightly indented at the base, the posterior 

 half raised instead of depressed ; the fosse distinct, as are also the corselet grooves ; the 

 margin somewhat rimmed or turned up ; caput elevated ; cephalic sutures distinct ; the 

 head rather stumpy and wide at the face. Color yellow or orange brown, with darker 

 streakings on the sides; a marginal rim of yellow surrounds the corselet, with a wider dark 



