NO. 2242. MORPHOLOaV OF THE STREPSIPTERA—PIERCE. 435 



(&) Mandibles broad, subquadrate, with apical tooth; base of head 0.62 as 



wide as cephalothorax at spiracles; distance from spiracles to apex 



0.80 the breadth at spiracles (Stylops, group 1) moestae. 



3. (a) Spiracles not prominent 4. 



(b) Spiracles prominent 23. 



4. (a) Mandibles without tooth 5. 



(b) Mandibles toothed 8. 



5. (a) Cephalothorax broader than long 6. 



(b) CephalothorMX longer than broad 7. 



6. (a) Base of head 0.56 as wide as cephalothorax at spiracles; base of 



cephalothorax 0.65 breadth at spiracles; length of cephalothorax only 



0.94 breadth at spii-acles [Neostylops, group 1) crawfordi. 



(b) Base of head 0.61 as wide as cephalothorax at spiracles; base of 

 cephalothorax 0.80 breadth at spiracles; length of cephalothorax 0.96 

 breadth at spiracles (Stylops, group 2) mandibularis. 



7. (a) Base of head 0.60 as wide as cephalothorax at spiracles; base of 



cephalothorax 0.72 breadth at spiracles; length of cephalothorax 1,10 



breadth at .spiracles; very small (Kntastylops) poletnonii. 



(li) Base of head 0.67 as wide as cephalothorax at spiracles; base of 

 cephalothorax 0.74 breadth at spiracles ; length of cephalothorax 1.03 

 breadth at spiracles; very large (Prostylops) . pilipedis. 



8. («) Mandibles with only one tooth, not angulate on side 9. 



(b) Mandibles with an apical tooth, and an angulation or tooth on side 17. 



9. (a) Cephalothorax broader than long 10. 



(&) Cephalothorax as long as, or longer than, broad 11. 



10. (a) Mandibles subquadrate with tooth at inner a'pical angle; base of head 



0.51 as wide as cephalothorax at spiracles ; base of cephalothorax 0.67 

 breadth at spiracles ; length of cephalothorax 0.87 breadth at spi- 

 racles {Stylops, group 3) nubeculae. 



(b) Mandibles rounded with tooth near apex; base of head 0.62 as wide as 

 cephalothorax at spiracles ; base of cephalothorax 0.54 breadth at 

 spiracles; length of cephalothorax 0.97 breadth at spiracles (Stylops, 

 group 4 ) subcandidae. 



11. (a) Cephalothorax as long as broad 12. 



(6) Cephalothorax longer than broad 15. 



12. (a) Mandibles elongate rounded 13. 



(b) Mandibles subquadrate 14. 



13. (o) Mandibles with tooth on inner side, surpassed by apex; base of head 



0.58 as wide as cephalothorax at spiracles; base of cephalothorax 

 0.74 breadth at spiracles; spiracles lateral, hardly prominent (Sty- 

 lops, group 5) krygeri. 



(h) Mandibles with acute tooth at apex; base of head 0.58 as wide as 

 cephalothorax at spiracle ; base of cephalothorax 0.82 breadth at 

 spiracles ; spiracles lateral, convex, but not strongly prominent 

 (Stylops, group 6) niultiplicatac. 



14. (a) Toolh of mandible near inner apical angle; base of head 0.56 as wide as 



cephalothorax at .spiracles; base of cephalothorax 0.87 breadth at 

 spiracles; spiracles barely marginal (Stylops, group 6) advarians. 



(b) Tooth of mandible apical; base of head O.GO as wide as cephalothorax 



•it spiracles; base of cephalothorax 0.78 breadth at spiracles; spira- 

 cles lateral, but not prominent (Stylops, group 6) bisalicidis. 



(c) Tooth of mandible halfway between apical angles; base of head 0.62 



as wide as cephalothorax at spiracles ; base of ceplialothorax 0.80 

 breadth at spiracles; spiracles slightly convex on margin but not 

 prominent (Stylops, group 6) i^parsipilosae. 



