OSTEN SACKEN ON WESTERN DIPTERA. 191 



Families CULICID^, CHIRONOMnXSE, PSYOHODID^. 



Half a dozen species of Culex, two Anopheles, and two Chironomus are 

 among my collections from California. They all exhibit the characters 

 and coloring peculiar to the species of these genera in other countries. 

 A Culex from Southern California is distinguished by very sparsely 

 bearded antennae of the male and a peculiar structure of the palpi. 

 Psychoda sp. — A single specimen ; San Rafael, Cal. 

 In the absence of any remarkable western forms, I describe two new 

 species from the Atlantic States. The first belongs to the little known 

 genus Aedes (Culicidce), of which only one species was known to occur 

 in the United States. The other is a second species of the new genus 

 Chasmatonotus (Chironomidce) established by Dr. Loew for a species 

 which I discovered in the White Mountains. 



Aedes fuscus n. sp., $ $ .—Brown ; thorax clothed with a short, 

 appressed, brownish-golden tomentum ; abdomen with whitish-yellow 

 narrow bands at the base of the segments 5 venter whitish-yellow. 

 Antenna? black ; proboscis and legs brownish, with a metallic reflection ; 

 femora paler on the under side ; pleurae under the root of the wings 

 I with a spot clothed with whitish scales. Long. corp. 3-4 mm . 

 Hob. — Cambridge, Mass., in May. 



Obs.—I bred this species from larvae which I found in a pool together 

 with those of several species of Culex. The larvae and pupa? behaved 

 1 exactly like those of Culex, and only attracted my attention by their 

 smaller size. If I could have known beforehand that they belonged to 

 Aedes,! would have compared them more closely with the larvae of 

 Culex. The metamorphosis of Aedes has never been observed before. 



Chasmatonotus bimaculatus n. sp., $ .—Black ; wings of the same 

 color and with two large white spots. Length about 1.5 mm . 



Black ; thorax shining j base of the abdomen laterally pale greenish- 

 yellow. Feet black ; front coxae and base of all the femora yellowish ; 

 I the first tarsal joints are of the same pale yellowish color, except the 

 (tip, which is black. Knob of halteres greenish. Wings black; the 

 first white spot is in the shape of a cross-band between the second vein 

 I and the anal angle; the second spot is square, and situated on the hind 

 margin, within the fork of the fifth vein. 



Hob.— Catskill Mountain House, in July, 1874; numerous male speci- 

 \ mens ; Quebec (Mr. Belanger). 



The first posterior cell and the cell within the fork of the fifth vein 

 • are much longer here than in C. tinimaculatus Lw., and the latter cell is 

 I larger and broader. Hence it happeus that although in both species 

 the cross-band-like spot is placed immediately inside of the proximal 

 end of the fork, it occupies the middle of the wing in C. unimaculatus , 

 ^and is much nearer the base in C. bimaculatus. The abdomen of the 

 male ends in a comparatively large and conspicuous forceps (the 

 "hypopygium maris globosum" in Mr. Loew's description of C. unimacu- 



