148 ENTOMOLOGICAL SOCIETY 



those illustrating the development of the malaria parasite and 

 that this polyembryony suggested the alternation of sexual and 

 asexual generations found in Protozoa and the trematodes. 

 As the rate of increase by the asexual mode is much more 

 rapid than that by the sexual mode it is fortunate for humanity 

 that in the case of the malaria parasite the period during which 

 reproduction can continue by the asexual mode alone is limited. 

 Certain phenomena resembling polyembryony, occurring in 

 other forms of animal life, were pointed out by various mem 

 bers present, and Doctor Phillips spoke of the artificial produc 

 tion of half and quarter embryos by chemical and mechanical 

 means and also referred to the work of Doctor Conkling on 

 ascidians, which seems to contradict the Mosaic theory of 

 development. 

 Mr. Banks presented the following paper: 



THE PSYCHODIDJE OF THE VICINITY OF 

 WASHINGTON. 



By NATHAN BANKS. 



For several years I have taken some interest in collecting 

 the Psychodidse wherever I have resided, and have now a dozen 

 species from the vicinity of Washington, four of which are 

 new. These tiny, delicate flies are not easily preserved for the 

 cabinet; it is necessary that they be mounted soon after cap 

 ture, and that no other insects be in the vial with them; so 

 that unless one goes especially prepared to catch them, his 

 captures will not be worth much. 



I have not had the facilities to attend to the rearing of any 

 of the species, but offer notes on the habits and habitats of 

 some of the forms. I am inclined to think that most of our 

 species do not live in water, but only in moist places. 



Psychoda alternate Say. 



Our most common species, taken in June, July, August, and 

 November. It is often found resting on out-buildings, and 

 doubtless breeds in muddy spots adjoining them. 



Psychoda cinerea Banks. 



Occurs on manure in the fields and woods, often far from 



