< The projection very broad, not narrowed toward tip . . Isetabilis 

 i The projection narrowed from base to tip . . . . lata 



\ P. M. E. less tiian diameter apart .... melanocnemis 



( V. M. E. more than diameter apart ...... 9 



\ Color dark gray or blackish ........ 10 



/ Color pale yellow or reddish . . . . . . . .11 



\ Tibial hook black, stout, cephalothora.K very dark . . brunnea 



I Tibial hook pale, slender, cephalothorax lighter . . . placida 



( Black of cephalothorax extends back to dorsal groove, very small white 



" \ species pygmsea 



' Black of cephalothorax confined to eye-region . . . . . 12 



f Tibial hook with two rounded teeth on side, narrowing toward the ti]), 



1 cephalothorax yellow emertoni 



I Tibial hook without such teeth, broad at tip, cephalothorax reddish 



[ similis 



Ccratiiiclla iiursta Bks. is a Lophocarcuuin, the only true species 

 of Lophocarciiiiiii described from U. S. Ccratinc/ia amuilipes Bks. 

 does not belong to the genus, I have a male from Poughkeepsie, 

 N. Y. , collected by Mr. Van Ingen, it is similar to the female, its 

 palpus shows some relation to the Theridina.^; I know of no genus 

 for it. Simon (Arach. d. France) has called our Crrati/icl/a Ccrati- 

 ic/i/s: but I consider that the name CeratiiicIIa was given not so 

 much to supplant Ceratiiia (preoccupied) as it was to designate 

 the species placed by its author (Emerton) under it. The European 

 forms called Ceratiiia are thus without a genus, I propose for 

 them Ceratiinnics. My CeratiiicUa fonnosa is not a true CeratiiicIIa. 

 1 propose for it Idioiiclla distinguished by the position of the horny 

 shield. I have collected it on Eong Island, N. Y. 



The females of our species of Aerosoiiia arc separable thus: 



.\bdomen with ten spines, three on each side and four at tip rugosa 



Abdomen with six spines, two on each side and two large ones at tip . spinea 

 Abdomen with four spines, all at tip ...... mitrata 



In the I'rairie Farmer 1861, p. 168, "Yespa" (Cyrus I'homas?) 

 mentions Gasteracaiitha spiiiicaiuia, this is a synonym of Aerosoiiia 

 spinea. Aerosoiiia boviiiiiin Thorell is a synonym of A . spinea. 



Our genera of the TetragnathiiKv may be sei)arated as follows: 



\ With a ventral furrow Qlenognatha 



\ No ventral furrow .......... 2 



I Abdomen not twice as long as witle, not much longer than the cephalo- 



I thorax Pachygnatha 



2 ' 



1 Abdomen more than twice as long as wide, much longer than the cephalo- 



[ thorax 3 



\ S. E. not farther apart then M. E Tetragnatha 



^ ) S. E. farther apart than M. E 4 



