52 Bulletin of the Brooklyn Entomological Society Vol. XIII 
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wigs such as Forficula (Fig. 25, “ pe”) might be termed mono- 
phallic, although traces of the original diphallic condition are re- 
tained in many cases. I have been much disappointed to find that 
in my material, the phallus of the Ephemerids is not very like that 
of the Odonata, nor does the phallus of either of them resemble 
that of the Neuroptera very much. The phallus of the Ephemerid 
shown in Fig. 9, “ pe,’’ is somewhat like that of the Plecopteron 
shown in Fig. 16, “pe,” and there is some slight resemblance in 
both to the phallus of the primitive Dermaptera (Fig. 24, “ pe”) ; 
but the similarity is not very striking. 
The phallus of the Isoptera available for study (Figs. 39 and 40, 
“pe”) is not well developed, which is rather surprising from the 
fact that the Isoptera exhibit other close resemblances to the 
Blattids and Mantids in which groups the phallus is well devel- 
oped. The phallus of most Blattids (Figs. 77 and 92, “pe”) and 
Mantids (Figs. 70 and 71, “pe” ) is strongly asymmetrical, and 
the structure of the phallus is essentially the same in both groups, 
which might be expected from the rather close relationship indi- 
cated by other structures. 
The phallus of the Phasmids (Figs. 51, 52, 54, etc., “pe”) is 
quite highly modified, even in such primitive forms as Timema 
(Figs. 42 and 65), and is disappointingly unlike that of the lower - 
Gryllids, Tettigonids, and Locustids, to which the Phasmids are 
undoubtedly closely related. The phallus of certain Tettigonids 
(1. e., “ Locustids”’) such as Peranabrus and Stenopelmatus (Figs. 
45 and 46) is faintly suggestive of the condition found in the 
Blattids and Mantids, but in the saltatorial groups, the phallus is 
apparently more symmetrical, and the parts are more closely 
united. Some Blattids (Fig. 82) are “aphallic,” or the greater 
portion of the phallus is either rudimentary or is united with the 
surrounding regions to such an extent as to be practically un- 
discernible. In most Mantids, however, the phallus is well de- 
veloped. 
It is an extremely difficult matter to interpret the parts of the 
phallus in all of the insects here figured, so that many of the 
homologies here given are purely tentative, subject to subsequent 
modifications based upon a further study of intermediate forms 
not at present available. In the most primitive insects such as 
