BULLETIN 39, UNITED STATES NATIONAL MUSEUM. [108] 



MUSEUM PESTS, MOLD, ETC. 



Unfortunately for the well-being of collections, dried insects are liable 

 to the attacks of various museum pests, the most troublesome of which 

 •are themselves insects, but altogether out of their proper place and 

 role in the general collection. Unless constant precautions are taken, 

 the collector will discover after a few months that instead of the rare 

 specimens with the preparations of which he has taken no little pains 

 there remains only a series of fragmentary specimens, which a few 

 years' neglect will reduce to little more than a mass of dust or powder. 

 The price, then, of a good collection is eternal vigilance. Most insects, 

 when exposed for any length of time to strong light, fade or lose color, 

 and the only way to prevent such achromatism is to exclude the light. 

 Insect pests affecting collections include Psocidse, Mites, Tineidse, 

 Coleoptera of the families Ptinidse and Dermestidse, these last being 

 the most injurious. 



The Psocidse — degraded wingless insects already referred to in the 

 classification (j). 24) — will find their way into the tightest boxes, but 

 ordinarily do little if any damage, except in the case of delicate 



insects, such as Ephemerids, Mi- 

 crolepidoptera, and Microdiptera. 

 The common forms found in collec- 

 tions are Atropos divinatorius and 

 Glothilla pulsatoria. Mites or 

 Acari are rarely troublesome in 

 collections, though Dr. H. A. 

 Hagen reports having found a 

 species (probably of Tyroglyphus) 

 with imported insects, and con- 

 siders them as liable to become 

 dangerous enemies. Tineid larvas 

 are rarely found in collections, and only affect the larger moths. They 

 are not easily discovered, since they make no dust, as do most other 

 pests. Some persons have been considerably annoyed by one of the 

 common clothes moths, Tineola Mselliella (Fig. 121). Dr. Hagen found 

 that it attacked freshly collected or newly spread insects, where the 

 spreading-boards were left uncovered, but Mr. F. M. Webster has found 

 it injurious to the general collections at Columbus, Ohio. 



Of beetles, the Ptinidse are sometimes found in collections but are 

 not common. Two species are known to attack entomological speci- 

 mens, namely, Ftinusfur, which is quite rare, in this country, but much 

 more abundant in Europe, and Triholium ferrugineum^ a cosmopolitan 

 species which, however, has several times been associated in injurious 

 numbers with large collections of insects imported from the East 

 Indies. 



But by far the most dangerous enemies of insect collections are the 



■'.rr^T' 



Tig 121 — Tu)( It hi^elhelln a adult b larva 

 cocoon and empty pupa — skm enlarged. 



