65 INSECUTOR INSCITI^ MENSTRUUS 



scales like those on the mesonotum. Pleurae light gray-brown, 

 with some small patches of whitish scales. Postnotum deep 

 brown, nude, with a pair of very distinct, ovate pruinose-white 

 spots. 



Abdomen depressed, truncate at tip ; dorsal vestiture of dull 

 black scales, the posterior margins of the segments narrowly 

 pale scaled, more broadly so at the angles, second and third 

 segments with an indistinct median triangular patch of dull 

 yellow-brown scales, its base at posterior margin of the seg- 

 ments ; first segment sordid white scaled and with many fine 

 yellowish hairs ; hairs on the other segments brown ; venter 

 clothed with white and black scales intermixed. 



Legs clothed with blackish and dull yellowish scales inter- 

 mixed, the dark ones predominating; front tarsi narrowly 

 marked with white at bases of first three joints, middle tarsi 

 at bases of first four ; hind tarsi with white rings at bases 

 of all the joints, narrow on first and second, broad on the 

 others, on the fourth joint occupying the basal half. Claws 

 slender, simple. 



Wings hyaline, the venation normal ; vestiture of very broad, 

 obliquely subtruncate scales overlying narrower ones, dull 

 black and white intermixed, the black ones predominating. 

 Fringe gray, unspotted. Halteres pale, with blackish knobs. 



Length of body, about G mm. 



Georgetown, British Guiana, December, 1915 (H. W. B. 

 Moore). 



Type, Cat. No. 20366, U. S. Nat. Mus. 



This species is -closely related to Mansonia titillans, but dif- 

 fers strikingly by the three large patches of golden scales upon 

 the mesonotum, as well as in other details. Theobald's M. 

 amasonensis and M. pseudotitillans are evidently closely related, 

 but apparently distinct. Further collecting will be necessary 

 to establish reliable diiTerences between these three species. 



Returning to Mansonia titillans and the question of oviposi- 

 tion, we have an interesting account of the process from Pro- 

 fessor Moore, sent under date of April 17, 1915, It is as 

 follows : 



