117 



Pupa — about 2miii. ; yellowish ; wing-cases extending nearly 

 to apex of 3rd abdominal segment, free at the tip; abdom- 

 inial segments 3-8 freely movable, apical edges somewhat pro- 

 duced and there are several spines on dorsal apical margins, 

 on ventral side are 2 spines per segment about midway between 

 base and apex; from the movability of the segments with the 

 assistance of these spines the pupa is capable of progressing 

 thru the material in which it lives. Compound eyes distinct; 

 two thoracic forward-projecting respiratory tubes. 



The length of time for the different stages was not ascer- 

 tained, nor other details of life history. When the flies emerge 

 from the pupae their wings develop with great rapidity, being 

 ready for use in a very few moments. 



Of the 34 species of Psychodidae described for North Amer- 

 ica, the life history of but one is known. This is Pericoma 

 calif omica Kincaid.* The larvae are elongate oval in form 

 and have a row of eight median ventral suckers by which they 

 cling to rocks in or on the margin of streams, where they are 

 constantly wetted by the dashing water. They breathe by 

 means of two spiracles at the posterior end. When ready to 

 pupate the larvae crawl a little higher on the stones, where only 

 the spray wall reach them, and fix themselves to the rock and 

 transform to small turtle-back shaped pupae in which they 

 remain about two weeks. 



Other species have been reared from manure, but the larvae 

 not obtained. Dr. Howard reared Psychoda minuta from cow 

 manure while making studies on the horn-fly. 



The life history of one British species is known. {Pericoma 

 canescens)'\' It lives in water, and feeds on green algae. 

 Three Brazilian. species have similar habits: Maruina Ursula, 

 M. spinosa and M. pilosella.*^ The larvae have a row of 

 8 suctorial discs on the ventral side by which they cling to 

 "rocky walls covered with a slippery carpet of algae, and kept 

 moist by the spray of waterfalls or by drops of water running 

 down from above." In two species, they have tracheal gills 

 situated at the posterior end of body; in one species the 

 tracheal gills are situated along sides, and a respiratory tube 

 at posterior end. They have two eyes. 



*Kellogg, Ent. News, p. 46, 1901. 



tMiall and Walker, Trans. Ent. Soc. London, p. 141, 1895. 



**Mii]ler, Trans. Ent. Soc. London, p. 483, 1895. 



