930 Charles Paul Alexander 



same type of situations as does the preceding species — beneath bridges, 

 culverts, in crannies of cliffs, on the inclined sides of boulders along 

 mountain streams, and in similar places. Their position when at rest 

 is very different from that of Dolichopeza americana, as they hang from 

 the roof by the front pair of feet only, the other legs dangling and the 

 wings being folded over the abdomen. In this last-named feature they 

 differ conspicuously from the often-associated Dolichopeza. The immature 

 stages are spent in moist earth, or (in the case of 0. ohscura) in a dry moss, 

 Hedwigia albicans, where they were first discovered by Hyslop. The 

 lai-vae are sluggish and of a rather dark green color. The following 

 key is adapted from one given by Johnson (1909:117-118): 



1. Tarsi, at least, entirely white 2 



Tarsi yellow or brownish 3 



2. Digitiform appendages of male genitalia short or rudimentary; ventral margin deeply 



and narrowly emarginate. [Proc. Boston Soc. Nat. Hist., vol. 34, p. 121, p!. 15, fig. 12. 



1909.] O. alhipes Johns. 



Digitiform appendages of male genitalia moderate in length; ventral margin broadly 

 emarginate. [Proc. Boston Soc. Nat. Hist., vol. 34, p. 121-122, pi. 1.5, figs. 5, 11. 

 1909.] 0. subalbipcs Johns. 



3. Halteres with the knobs dark brown 4 



Halteres entirely yellow 7 



4. Stripes of thorax distinct; ventral margin deeply emarginate 5 



Stripes of thorax obsciire ; ventral margin but slightly emarginate 6 



5. Pleura yellow, unspotted. [Proc. Boston Soc. Nat. Hist., vol. 34, p. 119-120, pi. 15, 



fig. 6. 1909.] 0. dorsalis Johns. 



Pleura yellow, spotted. [Proc. Boston Soc. Nat. Hist., vol. 34, p. 120, pi. 15, fig. 9. 

 1909.] 0. venosa Johns. 



6. Thorax opaque. [Proc. Boston Soc. Nat. Hist., vol. 34, p. 122, pi. 15, figs. 7, 10. 1909.] 



(Plate XLIII, 1S6.) 0. obscura Johns. 



Thorax shining. [Proc. Boston Soc. Nat. Hist., vol. 34, p. 122-123, pi. 15, fig. 8. 

 1909.] 0. obscura polita Johns. 



7. Ventral margin of male genitaha deeply and narrowly emarginate. [Proc. Boston Soc. 



Nat. Hist., vol. 34, p. 118-119, pi. 15, figs. 2, 3, 1909. New name for Tipula annu- 

 lata Say, Joiim. Acad. Nat. Sci. Phila., vol. 3, p. 25 (1823), preoccupied.] 



0. sayi Johns. 



Ventral margin broadly emarginate. [Proc. Boston Soc. Nat. Hist., vol. 34, p. 119, 



pi. 15, fig. 4. 1909.] 0. similis Johns. 



Tribe Ctenophorini 

 The following key separates the two genera of the tribe Ctenophorini: 



Antennae of male with three pectinations on the flagellar segments, each segment with a 

 single pectination on the apical half in addition to the usual basal pair; o\ipositor of female 

 greatly elongated, saber-like Tamjptcra Latr. (p. 931) 



Antennae of male with two pairs of pectinations on the flagellar segments, one pair being 

 subbasal and the other subapical; ovipositor of female short and of the normal tipuline 

 structure Ctenophora Meig. (p. 931) 



