TRIBE ASPIDIOTINI 



437 



than median lobes, deeply lacinate, those of each third in- 

 cisura and of lateris unapectinae, arranged 2, 2, 3, 6-7, those 

 of each lateris longer than others; anus over four times 

 its width distant from caudal margin; setae slightly longer 

 than lobes; densariae of second and third incisurae typical. 



Canary Islands on Dracaena. tinerfensis Lindgr. 



bb. Pygidium without pectinae or plates on each lateris. 



c. Pygidium with pectinae or plates of second and third incisurae 



longer than second and third pairs of lobes. 



d. Pygidium with median pair of lobes with distinct mesal and 

 lateral notches, quadrangular, large, distal end bluntly round- 

 ed; second pair of lobes similar in shape, about one-half size 

 of median; third pair of lobes small, pointed; pectinae sub- 

 equal in length to median pair of lobes, those of second and 

 third incisurae unapectinae, arranged 2, 2, 3, 0; each lateris 

 crenulate with two or three distant truncated plate-like pro- 

 jections; dorsal oraceratubae present. Abyssinia on Aloe 



mammillaris Lindgr. 



dd. Pygidium with median pair of lobes entire, large; second 

 and third pair of lobes much smaller, those of third pair 

 dentiform; pectinae small and delicate, arranged 2, 2, 2-3, 0; 

 dorsal oraceratubae numerous; cephalic end of pygidium with 

 two transverse calles, mesal and lateral evidently fused. 



Algeria on Ephedra. trabuti Marchal. 



cc. Pygidium with pectinae or plates of second and third incisurae 

 notably much shorter than second and third pairs of lobes, 

 those of third incisurae larger and with some notches, ap- 

 parently arranged 2, 2, 3, 0; median pair of lobes projecting; 

 second pair of lobes triangular, mesal side parallel with meson, 

 lateral side oblique, continuous with margin of pygidium; 

 third pair of lobes similar in form to second, but smaller and 

 more obtuse; setae long, extending much beyond lobes; para- 

 physes wanting; bundle of long and straight ceratubae on each 

 side of pygidium. South Tunis on Nitraria.__mtremo,e Marchal. 



. Pygidium without pectinae or plates in median incisura. 

 b. Pygidium with pectinae or plates on each lateris. 

 c. Pygidium with pectinae in incisurae. 



d. Pygidium with mesal densariae of second incisurae larger 

 than lateral, its cephalo-lateral angle produced; median pair 

 of lobes subquadrangular, mesal margins strongly convergent, 

 lateral and distal margins rounded, prominent lateral notch; 

 second and third pair of lobes minute, triangular, second 

 pair much broader than third; pectinae deeply lacinate, ar- 

 ranged 0, 2, 3, 4-5, those of each lateris and of incisurae una- 

 pectinae; cephalic end with four calles; setae long and 

 slender. Canada, District of Columbia, Mexico, Demerara 

 on basswood, lilac diffinis Newst. 



dd. Pygidium with mesal and lateral margins of densariae of 



