52 U.S. NATIONAL MUSEUM BULLETIN 248 posthdmous 



and postocular carinae; size and shape of segments 1 and 2 of antennae 

 in males ; carinae of prothorax and acetabular bars of pterothorax ; attach- 

 ment of head with prothorax; and to a certain extent the shape and pig- 

 mentation of the abdominal sclerites. 



The male genitalia are very small (except basal plate) and do not always 

 show differences of value ; in many cases the parameres and endomera are 

 invisible. The chaetotaxy of the male is practically the same in all species, 

 except slight differences in length of certain setae. 



The females may be separated by most of the characters listed above, 

 but the most dependable characters are: Shape of head and shape and 

 chaetotaxy of abdominal segments VIII-IX (IX is the "claspers"). The 

 fringe of setae on posterior margin of sternite VIII and the short, trans- 

 verse setae along the lateral margins of the "claspers" are excellent char- 

 acters, especially the number and length of those along the outer margin 

 of the "claspers." 



Enlarged figures of these structures for all females discussed will fully 

 illustrate these differences. 



For example: In araucuanus, new species, most of the setae on sternite 

 VIII are very short but the transverse setae of the "claspers" (most always 

 present) are entirely absent. These short, thickened setae of the "claspers" 

 range in number from 2 to 8. Except for size of body, antennal structure, 

 and abdominal segments VIII and IX, very little sexual dimorphism 

 is present. 



Oxylipeurus araucuanus, new species 

 Figures v:10,11,16 



Holotype female, allotype male, and 2 paratypes from Ortalis araucuan 

 (Spix) collected in eastern Brazil (in Emerson collection). 



Diagnosis : This is one of the larger species from the avian genus Ortalis, 

 the male is equal in size to variegatus, the female is larger (body, 2.34 

 against 2.22), and slightly larger than the female of garrulae. The male 

 head is longer than that oi postemarginatus but the same width at frons and 

 temples; the head of female is longer and narrower at both frons and 

 temples. 



Unfortunately the male genitalia are not clearly visible. They seem to 

 resemble those of huilensis, but the parameres are narrower and less curving ; 

 and the endomera, while of the same type, apparently differs. 



The genital claspers of the female resemble those of variegatus, no trans- 

 verse setae are along their outer margins, and the shape of segment VIII, 

 as a whole, is quite different (see figures). 



