CHARLES W. METZ. 105 



CRESSONI DIVISION. 

 This division is characterized in the males by the presence 

 of a number of tooth-like projections, forming a sort of comb 

 on the outer margin of each wing of the seventh ventral 

 plate ; and also by the upper extensions of the lateral face 

 marks, which diverge from the orbital margin, or project 

 mesad above antennal sockets. Within the division are three 

 smaller groups. The first includes P. cresso?ii, P. rudbecki^e, 

 etc., distinguished by having short, stout, teeth on the seventh 

 ventral plates, and stout, or clavate upper extensions of the 

 lateral face marks. The second group has short winged 

 seventh ventral plates with long, narrow teeth, and has 

 short, tapering upper extensions of the lateral face marks : 

 this includes P. tridentulus, and P. grossicornis. The third 

 includes only one species, P. varifrons, having long, narrow 

 wings of the seventh ventral plate, and quite different eighth 

 ventral plate and face marks from the others. The division 

 is not restricted geographically, representatives being found 

 in all parts of the country, but it is best represented in the 

 Rocky Mountain States. 



PKOSOPIS CRESSONI Ckll. 1907. 

 1869. P.pygmcea, Cr. Proc. Bos. Soc. Nat. Hist. 12:272. 



1895. P.pygmaa, Rob. Tr. Amer. Ent. Soc. 22 : 116. 



1896. P. pygmcea, Rob. Can. Ent. 28 : 136. 



1898. P.pygmcsa, Ckll. Ent., 1898, p. 217. 



1899. P. pygmcsa, Ckll. Ent. News. 10 : 3. 

 1901. P. pygjncsa, 'Low. Ent. News. 12:5. 

 l^Ol. P. pygmcga,'Lov. Ent. News. 12:78. 

 1904. P. pygmcBa, Rob. Can. Ent. 36 : 273. 



1906. P.pygmcea, Bull. Amer. Mus. Nat. Hist. 22: 423. 



1907. P. cressoni, Ckll. Ann. and Mag. Nat. Hist. Ser. VII. 20 : 131. 

 V^m. P.pygnicsa,\.ov. Ent. News. 10:3. 



V^\Q. P.pygni(sa,\.ov. Psyche. 17:178. 



Syn. {P. pasadence, Ckll.). 

 1810. P. pasadence, Ckll. Ann. and Mag. Nat. Hist. Ser. VIII. 

 5:30. 



Syn . ( P. labialifrofis, C kll . ) . 

 1896. P. labiatifrons, Ckll. Psyche. 7:437, 

 V^^\. P. labiatifrons,\.o\. Ent. News. 12:7. 



TRANS. AM. ENT. SOC, XXXVII. (14) 



