212 GENITALIA OF MALE DIPTERA AND MECOPTERA 



Having determined that the basal segment of the two-seg- 

 mented genital style gs of the mecopteron shown in figure 25 is 

 in all probability the basal segment of the two-segmented gono- 

 stylus ex of figure 4 (rather than the homologue of the coxite p 

 of figure 4), it naturally follows that the structure labeled gs 

 in the mecopteron shown in figure 6 (which is in every way 

 homologous with the basal segment gs of the two-segmented 

 genital style of the mecopteron shown in figure 25), likewise 

 represents the basal segment gs of the gonostyle ex of the ephem- 

 erid shown in figure 4, and it is a very simple matter to compare 

 the parts of the claspers of the mecopteron shown in figure 6, 

 with those of the dipteron shown in figure 9. Thus, the eighth 

 abdominal tergite 8* of figure 6 is homologous with the eighth 

 tergite 8* of figure 9, and the ninth tergite 9* of figure 6 is homol- 

 ogous with the ninth tergite 9* of figure 9, while the basal seg- 

 ments of the gonostyli gs, which are located on either side of the 

 ninth tergite 9* in figure 6, very evidently correspond in every 

 way to the basal segments gs of the gonostyli, which are also 

 located on either side of the ninth tergite 9* in figure 9, and the 

 second segments h of the gonostyli bear very similar median 

 processes in both insects. 



A study of the lower insects would suggest that the two- 

 segmented genital styles ex of figures 4, 5, etc., are modified 

 exopodites of the limbs of the ninth abdominal segment, so that 

 if this be correct, it is easily seen that the two-segmented genital 

 styles ex of figures 25 and 26 are also merely modified exopodites 

 of the limbs of the ninth abdominal segment, and consequently 

 the two-segmented genital styles ex of figure 9 (which correspond 

 in every way to the structures bearing the same labels in figure 6) 

 are possibly merely the modified exopodites of the limbs of the 

 ninth abdominal segment. Berlese confuses the basal segments 

 gs of the gonostyles ex of the ninth segment with the tenth 

 sternite (and even with the parapodial plates of Dermaptera, 

 etc.), and Newell has gotten the interpretation of the i)arts into 

 such a snarl in the Diptera and Hymenoptcra that it is hopeless 

 to try to find out what is really intended in her drawings, though 

 I suspect, from her figures of the Mecoptera, that she would 

 iiiterpret the basal segments of the genital styles as the ninth 



