42 



THOMAS SAY FOUNDATION 



the segments in front of it bear paired dorsal humps at 

 the sides. The large U-shaped supra-anal process is 

 wholly concealed when at rest between the subanals and 

 the divided halves of the tenth segment. We show it ex- 

 truded in one of our figures. Its morphology was carefully 

 worked out bv Miss Lucy W. Smith in her Monograph 

 (Trans. Amer. Ent. Soc, 43: 457, 1917). The genital 



plate of the female (eighth ven- 

 tral abdominal segment) is chitin- 

 izecl in the middle portion only, 

 and the form of its apical margin 

 is of first importance in determin- 

 ing species. This is easily seen 

 in fresh, or in well preserved alco- 

 holic specimens; but it dries in a 

 great variety of shapes in pinned 

 specimens, and external appear- 

 ances are not always to be trusted. 

 It is often necessary to relax such 

 specimens by boiling in order to 

 make certain determination. There 

 is a narrow inconspicuous band 

 of prickly pubescence, more or 

 less interrupted in the middle, 

 extending across the ninth ab- 

 dominal sternite on its apical 

 margin. 



After finding the male of Pt. 

 regularis associated with females 

 that agree with Hagen's type fe- 

 males, it seems apparent to us 

 that the male referred by Miss 

 Smith to Pt. regularis cannot be 

 Pteronarcella hadia that species. After careful com- 

 Ha £- parison of long series of speci- 



mens, both pinned and alcoholic, we believe hers to have 

 been the unknown male of Pt. badia; and we believe that 

 her Pt. torosa male was only another variant of the same. 

 The differences stated in her key (Trans. Amer. Ent. Soc. 

 43:458) seem considerable, but they are all relative, and 

 deal with very variable characters. Especially do the 

 paired dorsolateral knobs on some of the abdominal seg- 

 ments seem definite structural characters, until one dis- 

 covers that whether they appear or not on a given seg- 

 ment may be due to contraction in drying. The width of 



Pig. 11. 



