14 Annals Entomological Society of America [Vol. X, 



Very recently, Mr. R. C. J. Swinhoe has sent me many spec- 

 imens of Burmite, or Burmese amber, containing insects. This 

 material occurs in clay beds of Miocene age, but it is evident 

 that the amber was washed into them from higher levels, and 

 it is not impossible that it is much older. The insects, so far as 

 yet examined, have rather a primitive aspect, but the number 

 of species as yet available is small. I find a Termite {Ter- 

 mopsis), a Psocid (doubtfully referred to Psyllipsociis), an 

 Hemipteron of the interesting genus Enicoce phalus , a Trigo- 

 nalys, two extinct genera of Evaniidas, both very small, an 

 extinct genus of Empididae, a Sciara and a species of the 

 Psychodid genus Trichomyia. It is expected that more of this 

 amber from Burma will be available, and we may ultimately 

 get a good idea of a Tertiary insect fauna in tropical Asia.* 



It is not necessary to review the quite numerous deposits 

 containing Miocene insects in Europe, but we cannot overlook 

 our own wonderfully rich Florissant shales. A short distance 

 west of Pike's Peak, resting on a base of granite, is an ancient 

 lake-basin containing laminated shales full of insect and plant 

 remains. The preservation of the specimens is often excellent, 

 even such minute and fragile creatures as Aphids being repre- 

 sented by numerous recognizable genera and species. The 

 number of described species is now about 1300; by far the 

 largest Miocene insect fauna known in the world. The cor- 

 responding European deposit, at Wangen on the Rhine, has 465 

 described species, but many others remain undescribed in the 

 University at Zurich. It is certain, however, that were all the 

 Wangen fossils worked up, the series would still fall far short 

 of that of Florissant. 



The presence of certain types which probably reached 

 America from the Old World, and the absence of any distinct 

 Neotropical element, suggest that the Florissant beds were laid 

 down subsequent to the beginning of the migration from Asia 

 by way of what is now Behring Strait, but before North and 

 South America were connected; that is to say, in the latter half 

 of the Miocene. Should mammals be found at Florissant, early 

 forms of the elephant group may perhaps be expected. Perhaps 

 the most remarkable of all the Florissant insects is the genus 

 Glossina, today known as an inhabitant of tropical Africa, 



* Since this was written a new lot has come to hand, including many species, 

 one an Elaterid beetle nearly 20 mm. long. 



