94 INSECUTOR INSQTIit MENSTRUUS 



transverse line, the outer third on each side extending obliquely posteriorly 

 therefrom in a slightly curved line ; the hind border of third segment con- 

 siderably but not fully approaching this conformation, these segmental 

 margins in both cases presenting the appearance of having been stamped 

 or impressed into this form. Pollinose marking of anal segment vsdthout 

 macrochaetae. Second and third abdominal segments vv^ith dense sub- 

 pectinate row of spinelike macrochaetae on hind margin becoming less 

 dense on sides, and w^ithout discal macrochaetae. Two lateral approxi- 

 mated marginal scutellar macrochaetae, and a heavy posterior marginal 

 widely separated spinelike nearly erect pair without any weak apical pair 

 between them ; disk of scutellum with spinelike macrochaetae. One or 

 two stemopleural, two postsutural, and no acrostichal bristles either before 

 or behind suture. 



Proboscis moderately slender, the part below geniculation equal to 

 about two-thirds of head-height, the part above geniculation about same 

 length. Palpi not represented by bristlets. Second antennal joint only 

 moderately elongate, the third a little less than twice as long. Male front 

 at vertex about equal to eye-width. No ocellar bristles. Epistoma not 

 strongly salient. 



Reproductive habit, probably leaf-larviposition of colored maggots. 



Type, Signosoma impressum, new species. 



This and the follov^ang allied genera to Uruhuasiopsis inclusive resem- 

 ble closely the P^rrhosiinae in habitus as well as in the feebly salient 

 epistoma. Eusignosoma has been dissected and found to possess a truly 

 straplike uterus. The other forms must be dissected and a comparative 

 study of the first-stage maggots of the P3Trhosiine and Epalpine Hies made 

 before we can refer each to its proper group with certainty ; but all seem 

 closely allied with Eusignosoma on external characters. 



Signosoma impressum, new species. 



Length of body, 9 mm., not including the abdominal spines ; of wing, 

 9.5 mm. One male, Uruhuasi Bridge, San Gaban Canyon, about 6,500 

 feet, February 3, 1 9 1 0, on flowers of Baccharis sp. 



Head wholly silvery-white, except the parafrontals which are greenish- 

 black and more or less silvery, and the frontalia which are light brown. 

 Antennae wholly dark brown or blackish, including arista. Occipital 

 and parafacial pile grayish, parafronteil pile black. Thorax and scutellum 

 black with silvery pollen leaving four quite heavy and nearly equal black 



