502 PROCEEDINGS OF THE NATIONAL MUSEUM vol. ii 



The labial palpi, from which the generic name has been drawn, are 

 large, 3-segmented, and without bristles. In the males, these struc- 

 tures may be elongated and recurved back over the head and the dor- 

 sum of the thorax to the extent that they reach the first abdominal 

 segment. In such cases, when the palpus is denuded of its vestiture, 

 the basal segment is never the longest of the three. The labial palpi 

 of the males may also be quite short, in which event the denuded basal 

 segment is always the longest of the three. In some species, this 

 basal segment is as long as, or even longer than, the other two segments 

 combined. Although the palpi of the males are always upcurved, 

 they may or may not be closely appressed to the head and thorax. In 

 any one species, the labial palpi of the female are always shorter than 

 those of the male. However, in those species in which the males have 

 considerably shortened palpi, those of the females are only slightly 

 shorter. In other species, the palpi of the females are much shorter 

 than those of the males. In still other species, the palpi of the females 

 are considerably elongated. The labial palpi of the females may be 

 upcurved, porrect, or drooping, but they are never recurved back over 

 the head and thorax. 



The thorax is prominently tufted anteriorly and posteriorly, the 

 vestiture being rough, deep, and very dense like that of the head and 

 palpi. In regard to the legs, the femora are similarly clothed, while the 

 hind tibiae are hairy rather than bristled. Forbes (1923, p. 25, fig. 19) 

 has figured and labeled in detail the neuration of the right wings of a 

 typical male acrolophid, A. popeanellus, stressing the fact that vein 

 Rs of the forewing extends to the outer margin. In this group, the 

 neuration seems to furnish little in the way of generic or specific 

 characters. Comstock (1924, p. 611) briefly described the venation 

 as follows : 



The venation of the wings is quite generalized; the base of media is more or 

 less preserved, and all the branches of the branched veins are present; there are 

 three anal veins in both fore and hind wings; in the fore wings the tip of the third 

 anal vein coalesces with the second anal vein. 



The abdomen is thickly covered with spatulate scales. In some 

 species, these scales are rather densely overlaid with elongate hairs. 

 In any one species, the abdomen of the female is longer, thicker, and 

 more distended than that of the male. In the males of some species, 

 secondary sexual characters are exhibited in the form of large tufts of 

 scales or elongate hairs arising from the terminal abdominal segments. 

 Except for the genital segments, the abdomen offers little in the way 

 of generic or specific characters. The female has two genital openings, 

 one for oviposition and one for copulation. The latter is surrounded 

 by a ventral genital plate near the tip of the abdomen. The form of 

 this large, heavily sclerotized plate may be used for the separation 



