4 
Psyche 
[March 
but most of the setae and bristles have been omitted in fig. 
1, to avoid making the figure too complicated to show the 
more important structures readily. 
The seventh tergite in Notiothauma bears a pair of re- 
markable tergal processes labelled be in fig. 1, which appear 
to correspond in a general way to the structures called the 
“bicornua” in the male Plecopteron shown in fig. 17, plate 
2, of vol. 13 of the Bulletin of the Brooklyn Ent. Society for 
1918, and this term has therefore been applied to the struc- 
tures labelled be in fig. 1 of Notiothauma. The “bicornua” 
of the seventh tergite in Notiothauma {be of fig. 1) appar- 
ently serve to support the genital structures when the tip 
of the abdomen is turned forward over the top of the abdo- 
men in the male insect. Since there are no such structures 
on the seventh tergite of the other Mecoptera I have ex- 
amined, it is possible that these remarkable processes are 
peculiar to Notiothauma among the Mecoptera. 
The abdominal segments (with the exception of the first) 
as far back as the eighth segment, in Notiothauma , are “dis- 
cleritous” — i. e., the tergal and sternal sclerites are distinct 
and separate (the tergites are denoted by the letter t and 
the sternites by the letter s in fig. 1) — and the spiracles 
labelled sp) are located in the pleural or lateral membrane 
between the tergites and sternites. The fulvous-colored 
eighth and ninth abdominal segments, however, are “syns- 
cleritous” — i. e., the tergites and sternites have united to 
form a complete ring or continuously sclerotized surface 
from dorsal to ventral sclerite, and the spiracle of the 
eighth segment (which is larger than the preceding ones) 
is surrounded by the sclerotized surface, instead of being 
located in a pleural membrane. 
In Panorpodes the eighth and ninth segments are syn- 
scleritous (tergites and sternites fusing completely) and 
the seventh segment is partially synscleritous, the fusion 
of the tergite with the sternite being complete in the an- 
terior half of the segment, but the posterior half retains 
a partial division between tergite and sternite. Panorpodes 
thus presents an intermediate stage between Notiothauma 
(in which only the eighth and ninth segments are syn- 
scleritous) and the Panorpidse in which the seventh, and 
