CASTES OF TERMOPSIS 529 



not of the winged adult, has a flavor of the neoteinic or 'substitu- 

 tion' idea, which seems in disharmony with his other views and 

 which I am unable to support. 



We know also to-day from the work of Morgan and his school 

 that many characters are controlled by a single factor and, con- 

 versely, that a character may be affected by several factors. The 

 many characters of a termite caste are undoubtedly correlated, 

 and probably hnked in heredity; indeed a caste, like sex, may de- 

 pend upon one factor. We may make hypothetical mendelian 

 formulae, but as yet there are no exact data from breeding to test 

 by the formulae. We may talk about the expected results, but 

 we need the actual ones. We do not know the ratio between 

 the number of fertile and sterile forms. We are not absolutely 

 sure whether the second and third forms arise from parent first 

 forms or from parents Hke themselves, nor whether each repro- 

 ductive type is capable of producing the sterile workers and sol- 

 diers. A few breeding and field observations exist; for example, 

 Feytand ('12) states that the first brood in a new colony consists 

 only of sterile forms, workers; Snyder ('15) observed in several 

 genera that the first brood is composed of both workers and sol- 

 diers, and in a definite ratio, according to the species or genus; 

 but more data are needed, and must be obtained to complete the 

 evidence for the hereditary origin of the termite castes. 



SUMMARY 



1. The two species angusticollis and nevadensis of the genus 

 Termopsis are found on the Pacific slope and in the northwestern 

 United States. 



2. The habitat is the decaying wood of forests, very rarely in 

 buildings, and never in the earth. 



3. Four stable castes are of common occurrence; the first form, 

 the second form, and the third form are the fertile reproductive 

 castes; among the soldiers the females are sterile, the males are 

 probably also sterile, though near fertihty. There is no true 

 sterile worker caste. 



4. The sexes are differentiated externally in all castes. 



