289 



Academy of Natural Sciences, Philadelphia; and Prof. T. D. A. Cock- 

 erell, Boulder, Colo. To W. R. Walton, U. S. Bureau of Entomology, 

 I owe thanks for assistance in various ways. 



Prof. O. A. Johannsen submitted his unidentified specimens of 

 Ceratopogoniiice and examples of several species described by himself, 

 acknowledgments of which are inserted in the text. Mr. C. W. John- 

 son kindly examined the type of Be::cia opaca Loew at Cambridge, 

 Mass., at my request, and supplied information thereon. 



Keys to Subfamilies 



LARVJE 



1. Abdominal segments with stout spines, generally some of them 



lanceolate or pectinate; both anterior and posterior pseudopods 

 present; generally living under bark, in decaying wood, under 

 cow manure, or in the nests of Hymenoptera, rarely on submerged 

 logs Ceratopofjonincv, pt. 



— Abdominal segments usually bare, at most with weak hairs ; pseudo- 



pods present or absent ; aquatic in habit 2 



2. Both anterior and posterior (thoracic and anal) pseudopods absent ; 



snakelike larvffi Ceratopogonina', pt. 



— Both pairs of pseudopods present 3 



3. Labial plate generally retracted, elongate in form, the apex slightly 



dilated and with 7 teeth or less ; antennae elongate, retractile within 

 the head for almost their entire length ; head generally elongated ; 

 ventral blood-gills never present Tanupina'. 



— Labial plate never retracted, its position always beneath the labial 



papillge, the apex with generally more than 7 teeth, or if the apex 

 is narrowed the teeth are carried, more or less distinctly, along the 

 lateral margins, and the sides diverge posteriorly, so that the apex 

 never presents a spatulate appearance ; head generally about equal 

 in breadth and length : antennae not retractile ; ventral ])lood-gills 

 sometimes present in Cliironomus Cliironomince. 



PUPiE 



1. Thorax and abdomen with long spinelike processes on dorsum ; body 



enclosed on last 2-3 segments within the larval exuvia; terres- 

 trial forms Ceratopogonina, pt. 



— Thorax without spinelike processes; body generally entirely freed 



from the larval exuvia ; aquatic forms 2 



2. Abdomen with leaflike or spinose dorsal processes; wing cases ad- 



herent to sides of thorax; the skin ehitinous, retaining its form 

 after emergence of the adult ; last segment of the abdomen ending 



in two rounded, tapering processes which are not ciliated 



Ceraiogoponince, pt. 



