Herbarium Moth

Eois ptelearia

Images coming soon.

The moth which is the subject of consideration is interesting because of the fact that in recent years it has become known as a destructive herbarium pest. The larvae attack the flowers, to some extent the leaves, and also to a less extent the hard fruits and seeds of specimens collected in the Southwestern States and in Mexico. Their ravages were first detected at the United States National Museum in the year 1890. Strangely enough, they show no appetite for species belonging to the flora of the Eastern and Northern States. It is believed that the insect is native to the region the plants of which it devours, but thus far no entomologist has reported its occurrence in the section of country from which it is supposed to come. The damage it is able to inflict upon specimens is very great, because of the very rapid multiplication of individuals which takes place.

An exceedingly interesting account of the insect and its destructive work was given by the late Professor C.V. Riley in "Insect Life," Vol. IV, p. 108 et seq. From this article the cuts which are herewith given have been extracted. Botanists can not too carefully guard against this and other insect plagues which multiply in their collections. A solution of corrosive sublimate and arsenic, such as is commonly employed for poisoning herbarium specimens, will do much to prevent the ravages of the larvae; but, as is pointed out by Professor Riley in the article to which reference has been made, additional safety from attack will be secured if all specimens, as they are received in the herbarium, are subjected to at least twenty-four hours' exposure to the fumes of bisulphide of carbon in an air-tight box or receptacle. This substance, as experience has shown, is destructive to all forms of insect life. Care should, however, be exercised in its use, as the fumes mixed with atmospheric gases make a highly explosive compound. The operation should never be undertaken in the presence of flame. It is not even safe to allow the fumes of carbon bisulphide to mingle in large quantity with the atmosphere of an apartment which is lighted by electricity. Accidental sparking, owing to some defect of the wires, may cause an explosion. Several bad accidents have occurred from the use in careless hands of this otherwise most valuable insecticide.