47 



NOTES ON A PLAGUE OF PSOCIDS 

 IN A FACTORY. 



By R. a. harper GRAY, M.A., B.Sc. (Agric), M.Sc. 



{Lecturer and Adviser in Agricultural Zoology, Armstrong College, 



Newcastle-wpon-Tyne.) 



The small insects belonging to the family Psocidae cannot as a 

 whole be regarded as injurious either to growing plants, or to plant 

 products in their manufactured state. Their food is said to consist 

 for the most part of minute fungi, such as moulds, and of animal or 

 vegetable refuse^, and they, therefore, are seldom attracted to any 

 material of value. 



From time to time, however, Psocids are recorded as being destruc- 

 tive to such objects as corks, books, insects in collections, etc., and in 

 most cases it seems likely that the objects attacked had been kept in 

 damp surroundings and were, therefore, affected with moulds or other 

 fungi. An instance is mentioned by Theobald, for example, in which the 

 Psocid Atropos divinator.ia was referred to him with the complaint that 

 it was appearing in large numbers from an old mattress, and "causing 

 some consternation^." 



The genera most often associated with this type of damage are 

 Atropos, sometimes known as "Book Lice" (owing, doubtless, to the 

 fact that they are frequently found in the neighbourhood of old books 

 or papers which have not been disturbed for some time), and Caecilius, 

 but it seldom seems to have been recorded that either has been respon- 

 sible for serious loss from the financial point of view. 



It may, therefore, be of interest to describe a case in which a stoppage 

 of work in an important factory where straw mattresses are made was 

 actually brought about by insects of the genus Caecilius (C. fedicularius^). 

 These psocids had established themselves to such an extent that when 



^ Cambridge Natural History, vol. v, p. 393. 



2 Report on Economic Zoology for the year ending September, 1910, in The Journal 

 of the South-Eastern Agricultural College, Wye, No. xix. 



^ Specimens were submitted to Dr Gahan of the British Museum of Natural History, 

 who kindly identified them as belonging to this species. 



