WERNER MARCHAND 149 



wood, and stones would be the probable hiding places. The larvae 

 under observation became very active and crawled out of the slender 

 dish, a height of 9 cm., and fell into the water of the basin pro- 

 vided. When collected and placed in a deep glass vessel with some 

 water, the entire mass took refuge behind the filter paper in the glass. 

 There they crowded side by side with their syphons projecting from 

 the upper edge of the paper. When disturbed and forced to take to 

 the water, they were found in thirty min\ites reassembled in the char- 

 acteristic gregarious fashion behind the filter paper against the 

 glass. 



For convenience in study, a majority of the larvae were transferred 

 when 1 day old to individual glass jars one-third filled with clean wet 

 sand from the lake shore and provided with strips of filter paper 

 soaked in muck from the creek bottom. The jars, which were the 

 common half pint jelly glasses recommended by Hine, were kept 

 covered with filter paper, held in place by the tin lid which had a disk 

 cut from its top to admit air. By renewing the moisture on the 

 strip of filter paper in the jars, the filter paper cover serves ideally 

 to control the humidity. 



A considerable number of the larvae were not separated, but were left 

 together for observation in a glass dish with a few strips of paper 

 saturated with muck from the creek. The young larva is briefly 

 described as follows: 



"The larva one hour after hatching [Plate 5, Fig. 80, a, b] is 1.5 mm. in length. 

 The following day several were found to measure 1.8 mm. The general color 

 is a dirty white with a tracheal system of waxy white, the abdominal contents 

 pale green, and the Malpighian tubules of a lilac color. There are 2 black 

 eye-spots located midway on the head capsule. The latter tapers to a sharp- 

 pointed mouth with a prominent pair of great hooks or mandibles. The seg- 

 ments are provided with typical, conical, truncated, prolegs, each armed with a 

 chaplet of medium long, brown hairs. The siphon which is carrot-shaped at 

 this stage is a prominent feature." 



Food in a variety of forms was furnished the larvae. They thrived 

 from the start on minute crustaceans, larvae of Stomoxys, mosquito 

 larvae, and young angleworms. Full grown angleworms were found 

 unsuitable, and larvae of the blow-fly and flesh-fly were not satisfac- 

 tory unless killed previously, as they were capable of killing or in- 



