April, I92I Bulletin of the Brooklyn Entomological Society 57 



A COMPOUND LARVA. 



By Howard Notman, Brooklyn, N. Y. 



The writer was recently engaged in collecting insects on one of 

 the trails in the Adirondack Mountains. In the course of this 

 pursuit a large chunk of wood was turned over in the hope of 

 catching Carabidse beneath. None were disclosed but a number 

 of small, slender, whitish translucent larvae were seen wriggling 

 among the decayed leaves. It was at first thought that they 

 might have strayed from some nearby carrion on which such 

 larvae are frequently to be found. Search was made in the 

 vicinity for a dead bird or mouse or snake. None such could be 

 seen. In the course of the search, however, a strange creature 

 was revealed. This creature seemed to be a large whitish worm 

 of about the thickness of a lead pencil and some four inches in 

 length which was making slow progress among the leaves. Upon 

 closer inspection it proved to be not a single creature but com- 

 posed of hundreds of the small larvae found first under the chunk 

 of wood. It was recalled that similar larvae had been noticed at 

 times under the bark of damp, much decayed logs ; and it was 

 concluded that this style of locomotion probably resulted from 

 an effort to preserve the moisture or slime of the bodies neces- 

 sary^ for the maintenance of life. It would be vain to imagine 

 what insect catastrophe had induced these larvae to migrate in 

 such a swarm, though doubtless due fundamentally to a need for 

 a more humid habitation. Perhaps some nearby log had been 

 moved. 



It was at first thought that the larvae might be lepidopterous, 

 since they had well developed black heads, but the writer finally 

 concluded that they were dipterous which surmise was confirmed, 

 by Dr. J. Bequaert, who pointed out an account of similar aggre- 

 gations of larvae of flies of the Mycetophilid genus Sciara, in 

 Johannsen's " Fungus Gnats of North America." 



