20 MISCELLANEOUS PAPERS. 



It was soon observed that the larvae in breeding jar No. -t fed on 

 the crustaceans and at the end of a few da_ys showed a distinct increase 

 in size. Those in the jars containing water soon died, and jar No. 3 

 did not appear to be a success, so all but No. -i were al)andoned. The 

 larva3 in this last, however, were separated and placed in similar jars, 

 one specimen in each, and reared to full size, the adult fly being pro- 

 cured the following spring. 



Since, as stated, three of the four jars started with were soon aban- 

 doned, what is said hereafter regarding the method used in rearing 

 pertains to the single one retained. A glass jar was selected so that 

 the actions of the larvs could be observed through it; a small jar 

 seemed desirable because the larvfe are predaceous and eat their own 

 kind as readily as anything else, for which reason it is necessary after 

 a short time to place only a single specimen in a jar; also, even a small 

 receptacle furnishes plenty of room, and the long series, which it is 

 desirable to have, takes as much space in the insectary as one cares to 

 give to a single species. Onl}^ the quantity of sand and other material 

 necessary to success should be placed in the breeding jar, as it is de- 

 sirable once in a while to look this material over carefully in order to 

 locate the very small specimens and And out what they are doing. 



All things considered, half-pint jelly glasses were found to be well 

 suited for the purpose and easil}^ obtainable. Covers proved to be 

 desirable in order to prevent too rapid evaporation of moisture, but 

 a small perforation or two in them was necessary to furnish ventila- 

 tion. As the muck which was tested as soil for the jars grew much 

 mold, clean lake sand was chosen as decidedl}" preferable for the pur- 

 pose. The covering of plant material mentioned furnished a rest- 

 ing place for the small crustaceans offered for food, and the larvte 

 themselves seemed to choose to remain in it in preference to burrow- 

 ing into the sand, although they were apt to be found in any part of 

 the jar. Algte made good material for covering, but only a small 

 amount could be used, and too much water was detrimental, as either 

 in excess tended to develop deca}^, and consequent!}^ a bad odor, which 

 was observed to be unfavorable to the insects. The principal point in 

 favor of the algte, as compared with some other things, was that they 

 contained no hollow stems or large pieces into which the larvas could 

 crawl, but still, because composed of small soft particles, furnished a 

 mat in which they" could hide. When it was desired to locate these 

 larvffi it was easily done by picking the mass to pieces. As odors, 

 which are often fatal to the larvae, were likely to develop from the 

 material put in for food and also from other sources, it was found 

 necessary to watch the jars continual!}^, giving them a thorough cleans- 

 ing once in a while, and perhaps putting in fresh sand and plant material 

 occasionally. 



