Occasional Papers of the Museum of Zoology 9 



two groups based on the presence or absence of a sternal pro- 

 cess or tubercle on abdominal segment i are recognized. Pyg- 

 rnacus is the only species in the key lacking this process, which 

 is also lacking in risi. Differences between the two species 

 have been indicated above. 



A short distance above the railway station at Gualan, Guate- 

 mala, the railroad crosses the Gualan River. Just above the 

 bridge a small stream from the right enters the Gualan River. 

 Much collecting was done along this small stream in January, 

 1905, but no gomphines were seen. In June, 1909, however, 

 there were two handsome species of Gomphoides and Pro- 

 gomphiis risi. A short distance above the mouth of the small 

 stream was a pool, shallow on one side and with a wall of veg- 

 etation on the opposite deeper side. The three species of gom- 

 phines were accustomed to fiy in to this sunny pool and alight 

 on leaves overhanging the deeper water. 



Progoinphus pyguiaeus Selys 

 Figs. 2, 4, 5, 12, 13, 14 



Description : Abdomen, male 23-25, female 22.5-23.5 ; hind 

 wing, male 19, female 20. 



Face brown, marked with gray as follows : lower part of 

 labrum, variable in extent, rhinarium entirely, and f rons above. 

 Rear of head indefinitely mottled green and brown, variable, 

 darker above, below varying from almost entirely green to 

 almost entirely brown. Thorax browai, marked with greenish ; 

 dorsal thoracic stripes wide. 



Legs brown to black and green or yellowish green ; the first 

 and second femora pale at base, above passing at once into 

 brown which passes into black ; below pale ; third femora large- 

 ly pale, the apical fourth or fifth brown above, the extreme 



