204 Afinals Entomological Society of America [Vol. XV, 



the coxites* of the eighth sternite, g2 the endopodites and g3 

 the coxites of the ninth sternite. The style of the abdominal 

 sternites cannot represent the "legs" (endopodites) but the 

 exopodites, unless we consider that the styles on the thoracic 

 coxae are not their homologies. In Machilis heteropiis Silv. the 

 "ovipositor" consists of two pair of appendages, one of which 

 represents the endopodite of the ninth sternite and the other 

 the endopodite of the eighth. A careful comparison of the 

 male and female genitalia in a representative series of species 

 of Machilis and allied genera would be of great morphological 

 value. 



CERCOPID MALE. 



In the male nymph of Philaeniis leucophthalmiis (Linn) the 

 gonapophyses arise in exactly the same place as in the female. 

 In the earliest instar of the nymph g2 is a small, single median 

 process, in the following instar it is bilobed at the apex (Figs. 

 5 and 6). In the last instar the genital processes are smaller 

 than in the female and gl are not in such close connection 

 with the eighth, sternite. A comparison of Figures 1 and 7 

 indicates the differences between the sexes. 



In the adult male the segment behind the eighth forms a 

 ring-like pygcfer with the ventral margin produced into a 

 pair of narrow, flat processes (gp) with a longitudinal line of 

 weakness along the middle of the ventral surface (Figs. 8 and 9, 

 gl or gp). The tenth and eleventh segment form the anal 

 segment, the posterior margin of the former being produced into 

 two large, thick spines curved downward (Fig. 8) and the 

 anterior margin into two small curved processes (Fig. 8). 

 From the middle of the area between the anal segment and 

 the gp of the pygofer arises three processes, a median penis 

 or aedeagus (Fig. 8, p) and a pair of genital styles (Fig. 8, gs). 

 The latter project well into the pygofer as apodemes (Fig. 8, gss) 

 for the attachment of muscles. 



If we dissect out an immature imago from the nymphal skin 

 shortly before the final moult we find that the apices of gp lie 



*Walker considers gl and g2 to be similar organs of the eighth and ninth 

 segments. This would make them both endopodites. Certain of the evidence 

 appear to favor his v'ew and we are quite prepared to accept it, but we have used 

 the term co.xites as their development in the Homoptera appear to indicate that 

 they are those organs, rather than the endopodites. 



