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PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. XXMII. 



gompJius naninus, which is unique in the genus by its small size 

 (abdomen 43 mm., hind wing 32 mm.) and by the simple structure 

 of the inferior appendage, the apices of which are not bifid or toothed, 

 as is the case in all the other known males. (See discussion under 

 Onychogomfhus'^: species, p. 313.) The remaining three species are 

 intermediate in size. All are distinguished by pale indefuiite colora- 

 tion, and all may be in reality the same species. (See fig. 38.) 



H. icterops Martin, from Java, is briefly described in "Mission 

 Pavie" from a specimen in De Selys's collection. Abdominal seg- 

 ment 7 is largely yellow, and this character, may separate it from 

 the other two. The first described species of this group of three is 

 sumatranus Kriiger from Sumatra. The remainmg species is unicolor 

 Martin, described from Siani. 



Fig. 38.— 'Wings of m\lk IIeterogomfiius cochinchixen.sis from Tonkin. 



ig. HETEROGOMPHUS UNICOLOR Martin. 



"Un male unique de Siam, Museum de Paris." Abdomen 52 

 mm., hind wing 48 mm. Face and frons entirely yellow. Thorax 

 brown, with a poorly defined darker brown humeral stripe. Abdo- 

 men brown, tinged above, especially toward the end, with blackish; 

 7 tinged with ^^ellowish. 



H. sumatranus is somewhat smaller; abdomen about 50 mm., 

 hind wing 42 mm. From the descriptions no defuiite distinguishing 

 characters are recognizable, and it is probable that unicolor is a 

 synonym of sumatranus. 



Genus MEROGOMPHUS Martin. 



The single species, paviei Martin, is known only from Tonkin 

 (presumably, since in the description of both genus and species no 

 locality is given). This is a large, handsome species; abdomen 48 



