202 The Philippine Journal of Science i9i3 



paper. When disturbed and forced to take to the water, they 

 were found in thirty minutes reassembled in the characteristic 

 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 recom- 

 mended 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 jar, 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 larva one hour after hatching is 1.5 millimeters in length. 

 The following day several were found to measure 1.8 millimeters. 

 The general color is a dirty white with a tracheal system of 

 waxy white, the abdominal contents pale green, and the Mal- 

 pighian 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 segments 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 Crustacea, larvae of Stomoxys, 

 mosquito larvae, and young angleworms. Full-grown angle- 

 worms were found unsuitable, and larvae of the blowfly and flesh 

 fly were not satisfactory unless killed previously, as they were 

 capable of killing or injuring even well-developed Tabanus larvae. 

 As soon as the insect becomes aware of the presence of food, 

 the claw-like mandibles are protruded from the head capsule, 

 and bury themselves in the live food like meat hooks. With a 

 slight curve dorsally, the larva's body is brought forward, and 

 a small portion of the food is lacerated. This is aided by a 

 twisting of the head and a pulling with the extended jaws. The 

 mandibles are brought together with a rapid clawing action, 

 the parts working in apposition. When prehension is effected, 

 the jaws move alternately upward and downward and laterally, 

 and the bolus is swallowed in fibrous strands. 



Seeking and devouring food is not a continuous operation as 



