742 CHARLES PAUL ALEXANDER 



are working may be brought into the laboratory and placed in the breed- 

 ing cages. This method may be followed with species of Tanyptera, 

 Ctenophora, and other genera. 



Fungicolous species, as a rule, also are easily reared. The entire fungus 

 in which the specimen is found should be brought into the laboratory 

 and placed in a jar on a bed of clean sand. The sand takes up the liquids 

 produced by the disintegration of the fungus and provides a place for 

 pupation. Species of Limnobia, Ula, and other forms are reared in this 

 manner. 



The chances for error in rearing are many. One must be certain that 

 there are no other larvae in the breeding jar with the one that is being 

 reared; else one of these other larvae might transform and emerge first, 

 and the results would be altogether misleading. The writer has had 

 this happen in his breeding cages, even after the utmost care had been 

 used to guard against it. Beling, the great German student of the 

 immature stages of crane-flies, made a few mistakes in the same way; 

 as, for example, in the case of his Trimicra, the larvae that he describes 

 being pediciine and probably a species of Dicranota or the young larvas 

 of a Tricyphona. What happened, presumably, was that Beling found 

 these pediciine larvae and placed them in rearing; in the same cage, bu!^ 

 unknown to the breeder, was a larva of Trimicra which emerged, and 

 naturally Beling thought it came from one of the larvae that he had 

 placed in rearing. It is usually easy to check up such errors. Thus, 

 the writer has placed in rearing the larvae of Penthoptera and, to his 

 surprise, had adults of Limnophila adusta emerge. Obviously larvae 

 of L. adusta got into the cage in spite of precautions, and emerged first. 

 When closely related species are concerned, however, it becomes a hard 

 matter to straighten the tangle. Hence a species cannot be reared too 

 many times, since each rearing checks up the previous results. 



The precaution to be taken in the case of mud-inhabiting or sand- 

 inhabiting species is to see that the mud or sand is baked or thoroly 

 desiccated in order to destroy all life in it. Then it may be remoistened, 

 and the larva or larvae chosen to rear may be put into the earth without 

 the chance that some unknown larva may be lurking in the medium and 

 may emerge first, and so bring about confusion. 



The writer has found that the most satisfactory way to rear small 

 tipulid larvae found in earth or sand is to place a small amount of baked 



