548 MOSQUITOES OF NORTH AMERICA 



difference whatever between the two groups of this subgenus. The difference 

 in the armature of the claws in the adult female represents only a degree of 

 development, correlated with the method of copulation. It is without special 

 significance, and does not warrant the division of the group. 



Janthinosoma has been recognized on the fringing scales of the hind legs. 

 This character, while distinct in a number of species is gradually evanescent in 

 others, until there are found some, clearly belonging to the group on larval and 

 other characters, but devoid of these scales. The group is a distinct one on larval 

 characters, all the species having the same peculiar lateral comb of the eighth 

 abdominal segment. These larvae (with one exception) have a strongly inflated 

 air-tube. The male genitalia, however, are not differentiated from Psorophora 

 and the structure of the female abdomen is the same. We therefore recognize 

 the group only as a subgenus. A single species (separated under the name 

 Ceratocystia) has the same habits, but the larva instead of having a swollen air- 

 tube has enormously enlarged antennge, which structure, curiously enough, 

 seems to possess essentially the same function as the enlarged air-tube. 



Certain species belonging to Janthinosoma (sensu restr.) have been shown to 

 be the carriers of the eggs of the large flies of the genus Dermatobia, whose 

 maggots infest animals and man. The Dermatobia eggs are fastened on the 

 under side of the base of the abdomen of the mosquito, in exactly what manner 

 has not been observed ; but they are so carried by the mosquito and hatch when 

 the mosquito bites a warm-blooded host. 



PSOROPHORA POSTICATUS (Wiedemann). 



Culex posticatus Wiedemann, Dipt. Exot, i, 43, 1821. 



Culex posticatus Robineau-Desvoidy, M6m. Sec. Hist. Nat. Paris, iii, 410, 1827. 



Culex posticatus Wiedemann, Aussereur. Zweifl. Ins., 9, 1828. 



Culex posticatus Giles, Gnats or Mosq., 278, 1900. 



Janthinosoma musica Tlieobald (in part, not Say), Mon. Culic, i, 255, 1901. 



Janthinosoma discrucians Giles (not Walker), Gnats or Mosq., 2 ed., 339, 340, 1902. 



Janthinosoma musica Giles (in part, not Say), Gnats or Mosq., 2 ed., 339, 340, 1902. 



Janthinosoma musica Theobald (not Say), Mon. Culic, iii, 126, 1903. 



Janthinosoma musica Lutz (not Say), in Bourroul, Mosq. do Brasil, 39, 71, 1904. 



Janthinosoma musica Goeldi (not Say), Os Mosq. no Para, 117, pi. 4, fig. 15, 1905. 



Janthinosoma echinata Grabham, Can. Ent., xxxviii, 311, 1906. 



Janthinosoma sayi Dyar & Knab (in part), Joum. N. Y. Ent. Soc, xiv, 181, 1906. 



Culex posticatus Coquillett, U. S. Dept. Agr., Bur. Ent, Tech. Ser. 11, 8, 1906. 



Janthinosoma posticata Coquillett (in part), U. S. Dept. Agr., Bur. Ent., Tech. Ser. 11, 



17, 1906. 

 Janthinosoma posticatus Dyar & Knab, Proc. Biol. Soc. Wash., xix, 161, 1906. 

 Janthinosoma coquillettii Theobald, Mon. Culic, iv, 153, 154, 1907. 

 Janthinosoma sayi, var. iam,aicensis Theobald, Men. Culic, iv, 157, 1907. 

 Aedes posticata Busck, Smiths. Misc. Colls., quart, iss., Iii, 63, 1908. 

 Janthinosoma musica PeiTassti (not Say), Os Culic. do Brazil, 151, 1908. 

 Janthinosoma sayi Theobald (in part), Mon. Culic, v, 119, 1910. 

 Janthinosoma sayi jamaicensis Theobald, Mon. Culic, v, 119, 1910. 

 Janthinosoma coquillettii Theobald, Mon. Culic, v, 120, 1910, 

 Janthinosoma echinata Theobald, Mon. Culic, v, 121, 1910. 

 Janthinosoma centrale Brethes, Bol. Inst. Ent. y de Patol. Veg., i, 20, 1912. 



Geiginax Desckiption of Culex posticatus : 



Fuscus, chalybeo-nitens; tarsis posticis nigro-ciliatis, apice albis. Longit. lin. 

 2 1/2. fem. Mexico. 



Antennae, proboscis, palpi fusca; certo situ obscure chalybeo-nitentia: caput 

 flavicans. Thorax detritus fuscus, parum chalybeo-nitens; abdomen distinctius 

 chalybeum; venter incisuris late albidis. Alae fusco-squamulosae; halteres flavi- 

 cantes. Pedes chalybei; femora usque ad apicem fere flavicantia; tibiarum posti- 

 carum apex et tarsi supra et infra ciliati, pilis nigro-fuscis, certo situ chalybescenti- 

 bus; tarsi postici apice late albi. Mus. de Winthem. 



