NEW MAI.LOl'HAUA. 201 



connected with the latter }jy wings from its Ijase, which 

 reach the [>rongs a short distance hack of their diver- 

 gence. Tliere are also develoi>ed in the walls of the 

 j)enis numerous small, granular chitinizations. 



Physostomum diffusum. (Plate Xl\', iig. 3), 



The cliitinous genital parts of this species are very 

 simple. There are present in the walls of the penis two 

 diver)j:in<i lateral rods which meet in front. Here thev 

 send forward into the body cavity a very small rod, it 

 being about a third of the length of each outer prong, 

 to which muscle fibers are attached. The posterior ends 

 of the prongs are connected by a transverse, angular bar. 



Menopon mesoleucum. (Plate XI\', tig. 10). 



A long, rather thick internal rod is present. This 

 arises from the united anterior ends of two thick bars 

 in the walls of the penis. These bars are very short 

 and do not nearly reach the end of the penis. To the 

 end of each is articuhited a longer tapering rod free 

 from the penis and reaching to its posterior end. 

 These have the apjtearance of being homologs of the 

 articulated lateral prongs in some of the Ischnoceran 

 forms, 



RESUME. 



From the preceding descriptions it is clear that the 

 outer genitalia of the male may be generalized as fol- 

 lows. The posterior end of the last abdominal segment 

 is invaginated to a varying extent, forming a genital 

 chamber surrounded by the walls of the body, possess- 

 ing a ehitinous lining continuous with the V>ody-wall, 

 and opening posteriorly to the exterior. Into its 

 anterior end the ductus ejacuhitorius opens, and the 



