402 Phylum Arthropoda 



In order to facilitate the study of ecdysis, individual larvae are 

 isolated in circular glass cells of approximately 1 1 mm. internal diameter 

 and 3 mm. height. These are cemented to 3" x 1" microscope slides with 

 Canada balsam. They are covered at the top with a circular cover 

 glass which is secured in place with vaseline. To maintain humidity 

 within, a circle of filter paper is cut to fit the cell, and on this a minute 

 pellet of the moistened powdered sterilized manure is placed. It has 

 been found that unless additional precautions are taken, excessive drying 

 out may result when the slides are kept in an incubator. To overcome 

 this, numbers of the slides are placed in a flat tin (tobacco tins are 

 commonly used) in which is placed a layer of damp sand, covered with 

 blotting paper. Both this and the filter paper in the cells require period- 

 ical, if not daily, moistening to maintain suitable conditions for larval 

 development. Providing that the food is renewed as required, larvae of 

 5. fenestralis pass through readily to adults in these cells. 



j. G. N. 



Family simuliidae 



SIMULIUM ORNATUM* 



LARVAE of all stages were collected by rapidly removing from the 

 u water weeds or stones on which they are wont to congregate. They 

 were then placed in jars containing water and transported to the lab- 

 oratory for rearing. 



Larvae were maintained alive for considerable periods of time in vessels 

 containing water through which a jet of compressed air, delivered 

 through a plug of porous wood, was passed. It was found, however, that 

 in spite of the provision of algal food, most of the larvae died. The 

 exceptions were mature larvae that were ready to pupate. Adult flies 

 have been reared from larval and pupal stages by Edwards (1920), 

 Cameron (1922), and others, and Puri (1925) states that he success- 

 fully reared 5. aureum and S. erythrocephalum from egg to adult in 

 bell jars filled with rain water, in which there was a growth of algae and 

 through which a jet of compressed air was passed. This method failed 

 to give the required results with 5. ornatum and eventually the apparatus 

 shown diagrammatically (Fig. 71) was designed, in which 5. ornatum 

 was successfully reared from the egg to the adult. 



The apparatus consisted of a large cylinder about 20 inches high and 

 5 inches in diameter, containing water with algal food in suspension. 

 Submerged in the water was a large-bore glass tube, up which the water 



* Abstracted from an article in Proc. Roy. Physical Soc. 22:217, 1934. by John Smart, 

 University of Edinburgh. 



