380 CAROLINE BURLING THOMPSON. 



Holmgren arises late in its development by molting from an 

 antecedent worker-like form with thirteen antennal segments. 



In view of these conflicting observations it seemed at first 

 possible that different degrees of differentiation of the newly 

 hatched nymphs, as well as differences in development, might 

 exist in the various genera of termites, and perhaps even among 

 the species of a genus, as, for example, in the genus Eutermes; 

 the nasutus of E. lacustris being clearly defined at the time of 

 hatching, according to Bugnion ; the nasutus of E. pilifrons 

 arising rather late in the development by molting from a worker- 

 like form, according to Knower. But, before coming to any 

 conclusion, it seemed desirable to have further data in regard to 

 the conditions among other termites at the time of hatching and 

 in the early stages of development. 



The present study of the newly hatched and the developing 

 nymphs of nine genera and thirteen species of American termites, 

 from both temperate and tropical regions, was therefore under- 

 taken for two reasons: first, to ascertain the conditions among 

 different genera of termites, and second, to determine whether 

 the development may vary within a genus, by comparing the 

 conditions in Eutermes lacustris, as described by Bugnion, with 

 those of Eutermes pilifrons, the Jamaican species observed by 

 Knower, and with two other tropical spec : es, E. morio Latreille, 

 and E. sanchezi Holmgren. 



MATERIAL. 



Dr. Knower has very kindly sent me an abundance of pre- 

 served material of Eutermes pilifrons, consisting of eggs, young 

 nymphs, winged adult reproductive forms, and adult workers 

 and nasuti. I am indebted to Mr. N. Banks, of the Museum of 

 Comparative Zoology, Cambridge, Mass., for the identification 

 of this species. 



Most of my material was furnished me by the Bureau of 

 Entomology of the U. S. Department of Agriculture, and much 

 of it was collected and fixed for me by Mr. T. E. Snyder, to 

 whom my sincere thanks are due. The eggs and young of 

 Termopsis I have collected myself at Pacific Grove, Cal., during 

 a visit to the Hopkins Marine Station. 



