V 



PAGE 



External characters 145 



1 ntcrnal characters 145 



Fridcricia IMichaelsen 151 



Key to the species of Fridericia known to occur in North America 152 



Fridericia douglascitsis, n sp 154 



External characters 154 



Internal characters 155 



Fridericia oconeensis, n. sp 159 



External characters 160 



Internal characters 160 



Fridericia si ma, n. sp 163 



External characters 164 



Internal characters 165 



Enchytrccus Henle 167 



Key to the species of Enchytrccus known to occur in North America. . . . 169 



Enchytrceus gilletteiisis, n. sp 170 



External characters 171 



Internal characters 171 



The penial bulb as a character in classification 173 



Observations and experiments on Liimbricillus mtilus n. sp 180 



Habitat 180 



Color of living specimens 184 



Locomotion 185 



Relation to light 186 



Relation to desiccation 186 



Thigmotactic response 187 



Behavior with reference to dry and moist surfaces 188 



Relation to temperature 188 



Relation to oxygen 189 



Relation to sewage 193 



Summary 202 



Bibliography 205 



Explanation of plates 211 



ARTICLE IV. NOTES ON NORTH AMERICAN DIPTERA, WITH 

 DESCRIPTIONS OF NEW SPECIES IN THE COLLECTION OF 

 THE ILLINOIS STATE LABORATORY OF NATURAL HIS- 

 TORY. BY J. R. MALLOCH. (3 Plates) June, 1914 213-243 



ChironomidcE 213 



Chironomiis compes Coquillett 213 



Chironomus fcrrugincovitlalus Zetterstedt 214 



Palpomyia and Serromyia 216 



Revision of species 217 



Notes on the early stages of Palpomyia 224 



A revision of the genus JohannsenicUa for North America 226 



Synopsis of species (females) 226 



