136 PROCEEDINGS OF THE NATIONAL MUSEUM 



5 females. There were three pairs in copulation, and all were from 

 the same locality. As in most other species of the genus, they are 

 without developed luminous organs. Also in common with other 

 species, the elytra of the females vary considerably in relative length, 

 and from 1 to 3 abdominal segments are exposed. While occasional 

 small specimens of P. obscura, P. albomarginata, and P. rhododera 

 approach the length of this species, here named P. minor, these spe- 

 cimens may be distinguished by the specific characters. The holo- 

 type, female allotype, and five paratypes have been sent to Pena. 



AEDEAQI 



The aedeagi were extracted after they were relaxed in a moist 

 chamber, dried in acetone a few minutes, and immediately mounted 

 on Nylon filaments with Duco cement. The base of the filament was 

 cemented to a point, which was then pinned like a specimen. Meas- 

 urements were made on the mounted aedeagus, and outline drawings 

 were made with a camera lucida. 



Comparisons of the aedeagi revealed that by simple inspection of 

 the specimens, P. bifenestrata could not be definitely separated from 

 P. obscura. Small specimens provisionally classed as the former 

 sometimes showed the aedeagus characteristic of the latter, and vice 

 versa. Except for the aedeagus of bifenestrata, there is some general 

 resemblance in this organ among the various species. In P. nigri- 

 pennis and P. depressicornis, the lateral lobes were usually more or 

 less spread as shown in the drawings. Since some of the species were 

 originally described as Lucidota, it seemed worthwhile to compare 

 the aedeagus of Lucidota atra, which, like Pyractonema, is diurnal and 

 nonluminous, with those of the latter genus. The long, narrow struc- 

 ture of this organ in atra, however, is not comparable to that of any 

 of the species of Pyractonema except possibly bifenestrata, and it lacks 

 the broad cultriform median lobe of the latter. Somewhat surprising 

 is the fact that the aedeagus of bifenestrata should be noticeably 

 different from those of its congeners. The aedeagus of Lucidina 

 puerile E. Olivier, from Japan, is similar in form to that of P. bifene- 

 strata, but the median lobe is not cultriform and the lateral lobes have 

 expanded apical portions. 



The outline drawings which I have included are intended as aids in 

 identification ; however, I do not attempt to indicate internal structure 

 or function of parts. 



MISCELLANEOUS NOTES ON VARIANTS AND LARVAE 



A few specimens, all males and mostly from Parral, did not quite 

 meet the descriptions of the species given herein. Examination of the 

 aedeagi showed them to be much like that of P. bifenestrata, and these 



