DIAPERINI NORTH OF MEXICO — TRIPLEHORN 355 



through extension tubes by Dr. John C. Moser, whose generous aid 

 is hereby gratefully acknowledged. 



Biology. — Information on life histories, immature stages, and hab- 

 its of the North American species of Diaperini is extremely fragmen- 

 tary. Apparently, they are almost all associated with fungi, either 

 feeding on mycelia under bark or in sporophores and occasionally on 

 fungi growing on other organic material. A number of species in the 

 genera Platydema, Neomida, and Diaperis are recorded on fungi in the 

 genera Polyporus and Fomes. Gebien (1925) has suggested that since 

 both of these fungus genera are distributed throughout the world, 

 there is no doubt but that this alone explains the wide distribution of 

 the Diaperini and the Boletophagini. He supports this dogmatic 

 statement with an impressive list of species of Polyporus and Fomes 

 along with their world distribution, illustrating the surprisingly wide 

 dispersion of many of them. Fomes obliguus Pers., for example, occurs 

 in Europe, North and South America, the West Indies, Africa, Ceylon, 

 and Australia; Fomes pectinatus lOotzsch., appears in Europe, North 

 America, Australia, Java, the Philippines, India, and Africa; Polyp- 

 orus gilvus Schwein., appears in North and South America, the West 

 Indies, Africa, Australia, New Guinea, the Malay Archipelago, and 

 East India. Unfortunately it is not known to what extent any of 

 the diaperines are host specific. It remains to be shown by actual 

 tests just how close these relationships are and as yet very few con- 

 tributions have been made toward this end. 



A perusal of the collection data accompanying specmiens of North 

 American Diaperini indicates that most of them are to be found in 

 the adult stage the year around, hibernating under bark in the more 

 northern latitudes. Some of them (e.g., Neomida bicornis, Diaperis 

 maculata, Platydema ruficorne, and P. excavatum) occasionally con- 

 gregate in large numbers ostensibly for this purpose. 



Two species, Alphitophagus bifasciatus (Say) and Platydema ruficorne 

 (Stimn), have entered the economic hterature as the two-banded fungus 

 beetle and the red-horned grain beetle respectively. Both have been 

 reported on a number of occasions mfesting cereal products, but in 

 no instance have they been observed attacking sound grain or freshly 

 milled products. It is only in situations where these products are 

 allowed to accumulate and spoil that the beetles are attracted to 

 them, in all probability to feed upon the attendant fungi rather than 

 the grain products themselves. These beetles are generally regarded 

 as of little or no economic importance. 



Specimens studied. — A total of 15,467 specimens of North Ameri- 

 can Diaperini, supplemented by several thousand specimens from ex- 

 tralimital areas, was studied. New characters which might help place 

 the tribe on a sounder basis were constantly sought. One that has 



