496 CAEOLINE BURLING THOMPSON 



the deeper heart wood ; very rarely in the woodwork of buildmgs, 

 and never in the earth. 



In normal colonies of T. angusticollis and T. nevadensis four 

 stable types or castes may be found: 1) the first-form adults, with 

 long wings at the time of swarming, and later with the scales or 

 bases of the broken-off wings; 2) the second-form adults, with 

 very short wing vestiges which are much shorter than in second- 

 form individuals of other genera; 3) the wingless third-form adults; 

 4) the soldiers. The first and third forms and the soldiers are of 

 common occurrence, the second forms are comparatively rare. 

 In addition to these four stable castes, three additional types or 

 variations are occasionally found. These are : soldiers with wing 

 pads (fig. 9), second-form individuals with very minute wing 

 vestiges (fig. 7), and individuals closely resembling the third 

 form, but with wing vestiges that are merely narrow lateral 

 borders of the thoracic segments (fig. 8). The nymphs of all 

 castes occur in different stages of development according to the 

 season of the year. No true sterile worker caste is known to 

 occur in Termopsis, although the wingless third-form individuals 

 have been frequently described by different writers as 'worker-like 

 forms' and even as 'workers. ' The worker functions are performed 

 by the developing njmiphs, especiallj^ those of the third forms, 

 and it is well known that the older reproductive forms do not 

 survive long in captivity unless in the company of nymphs. The 

 same is true of soldiers. 



:\IATERIAL AND METHODS 



Most of the material for this paper was collected by the wTiter 

 in the pine forests of Pacific Grove, California, in April and May, 

 1919, while a guest of the Hopkins Marine Station of Leland 

 Stanford University. I wish here to express my thanks for the 

 hospitahty of the station during this time. For the identification 

 of my collections and for additional material the writer is indebted 

 to Dr. T. E. Snyder, of the Bureau of Entomology, U. S. Depart- 

 ment of Agriculture. _ 



This study of Termopsis angusticolhs has been made chiefly 

 by means of serial sections and dissections of organs after stain- 



