SIMULIUM. 63 



sciitellum with closely placed yellow pilosity, and brownish, upright, 

 longer hairs. Abdominal basal fringe short, yellow; segments of 

 abdomen with short, sparse, yellow hairs, and longer, dark hairs at 

 apex. Legs with pale yellowish pilosity, which is whitisli at bases 

 of tibiiip and on basal joint of hind tarsi; dorsal surfaces with longer, 

 blackish, upright hairs; fore tarsi slightly dilated, the paired apical 

 hairs present on joints 1 and 3; claws simple. Wings with brown 

 hairs at base and brown surface hairs on thick veins; cross-vein at 

 two-fifths from end of subcosta. 



Length, 1.5-2 mm. 



Ti/pe.— Cat No. 15414 U. S. National Museum. 



Locality. — Santa Lucrecia, Vera Cruz, Mexico (F. W. Urich). 

 There is also a specimen from Cayamas, Cuba {Yj. A. Schwarz) 

 which evidently belongs to this species. 



The series taken by F. W. Urich is labeled " Bloodsucking, man, 

 October, 1911." 



The early stages and the male are unknown. 



ADDENDA. 



When the manuscript of this paper was under preparation I had 

 considerable doubt as to whether there were not several closely allied 

 forms confused under certain specific names, this being particularly 

 the case with mendionalc. That size can not always be accepted as a 

 safe guide to the separation of species is abundantly evident to any 

 student of insects, and although in the series of specimens in the Na- 

 tional Museum collection there was much disparity in this respect, 

 the specimens presented no tangible characters which, without the 

 confirmatory evidence provided by a knowledge of the early stages, 

 might be accepted as of specific value. Thus I left under one name 

 at least three forms which may in the larval and pupal stages prove 

 to be very dissimilar. The distinctions in the adults are very minute 

 in the genus Shnidium and are hardly appreciable to anyone unac- 

 quainted with the family. I am therefore pleased to have had access 

 to the material belonging to the Illinois State Laboratory of Natural 

 History because of the additional light the material representing the 

 early stages therein contained has cast upon the question of the num- 

 ber of species in the Tneridiowde group. Prof. S. A. Forbes has kindlv 

 given me permission to include the matter in this addenda as part 

 of my paper. 



Simulium forbesi, new species. 



Female. — Black, covered with a pale-gray pollinosity, which gives 

 to the insect a pale-gray appearance. Antenna^ and palpi black, the 

 former rarely slightly paler at bases. Scutum with three black vittae, 

 the central one narrow, the outer pair broader, more or less distinctly 



