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 

 Ccratopogonina: 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 Beasia opaca Loew at Cambridge, 

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



Keys to Subfamilies 



LARV^ 



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 Ceratopogonince, 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 larvge 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 Taiujpince. 



— Labial i)late never retracted, its position always beneath the labial 



papilla?, 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 ; antenna not retractile ; ventral blood-gills 

 sometimes present in Chironomns 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. A])domen with leaf like 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 



Cerafogoponina\ pt. 



