1931 ] 
Structure of Notiothauma reedi 
7 
The hypandrium or sternal portion of the ninth segment 
(andromere) is extremely interesting in Notiothauma (i. e., 
ha of figs. 7 and 21), and its condition in Notiothauma 
might be taken as the starting point for tracing the modifi- 
cations of the hypandrium of other Mecoptera (see ha in 
the different figures), although the hypandrium ha of 
Chorista shown in fig. 18 might also be taken as the start- 
ing point in tracing the development of the hypandrium in 
other Mecoptera. The hypandrial processes labelled h in 
figs. 18, 21, etc., have been termed the hypovalvse, hypo- 
processi, etc., but in the following discussion they will be 
referred to simply as the hypandrial processes. In Notio- 
thauma (figs. 1, 7 and 21) the hypandrium ha (which is 
divided into a basal and distal area) bears an unpaired 
median process and two lateral processes, while in Chorista 
(fig. 18) the median process is not developed, and there are 
small secondary mesal processes on the lateral hypandrial 
processes labelled h in fig. 18. In Merope (fig. 19) and 
Boreus (fig. 17) the hypandrial projections h are very 
slightly developed. In Panorpodes (fig. 20), however, the 
hypandrial processes h are well developed (and are pro- 
vided with peculiar outgrowths, as shown in fig. 20), and in 
the development of its hypandrial processes, Panorpodes 
approaches the Panorpidas more closely than any other 
lower Mecoptera do. In most Panorpidae, such as the one 
shown in fig. 22, the hypandrial processes are well devel- 
oped and in the Indian Panorpid shown in fig. 23, which 
has the most peculiar hypandrium of any Mecopteron I have 
seen, the hypandrial processes h curve about a somewhat 
circular basal opening, and are produced posteriorly into 
elongated processes which are modified apically to form the 
peculiar distal structures shown in fig. 23. The hypandrium 
is not prolonged posteriorly in the Bittacidae or Nanno- 
choristidse. 
The male genitalia proper consist of the gonopods ex and 
st of fig. 13 and the structures comprising what the Dip- 
terists call the phallosome, made up of the valvae and other 
projections about the penis or the genital opening — i. e., the 
central structures labelled ps in fig. 13. It is very difficult 
to interpret the homologies of the male genitalia in the 
