316 WHEELER— ANT LARVAE. 



Wasmaiin has shown in a number of papers that the true guests 

 of termites, the symphiles, are physogastric, i. e., have the abdomen 

 enormously distended with fatty tissue. This condition is very 

 striking in certain StaphyHnids {Xenoga-ster, Corotoca, Spirachtha, 

 Termitomimiis, etc.) and Diptera (Timeparthenus, Termkomyia, 

 Termitoxenia, Thaumatoxena, etc.). Triigardh (1907) has studied 

 sections of the beetle Termitominms, which lives in considerable 

 numbers in the Eutcnnes colonies of Zululand. His description of 

 the exudate organs is so much clearer than Wasmann's and so sig- 

 nificant in connection wath my account of the Pachysima larvae, that 

 I quote the greater part of it: 



The relation of ,the fat-body to the hypodermis and the cuticle is dif- 

 ferent in different parts of the body. 



1. The hypodermis is exceedingly thin, sometimes scarcely discernible 

 and pressed close to the cuticle by the underlying fat-body. The cuticle has 

 no distinct endostracum and is penetrated by an immense number of ex- 

 tremely fine pores, arranged in transverse rows. This is the case with the 

 ventral, lateral and posterior part of the pseudoabdomen, i. e., exactly where 

 the cuticle is of a bright reddish-ycllozv color ("symphilous color" Was- 

 mann) and where the termites may most easily get access to it. 



2. The hypodermis is thick and withdrawn from the cuticle which is 

 thicker, with well-developed epiostracum and endostracum, leaving a rather 

 wide space, which is filled with liquid. . . . The fat-body is contiguous to the 

 hypodermis. The space between the cuticle and the hj'podermis is more or 

 less filled with a cyanophilous tissue of a spongy appearance which sometimes 

 exhibits a very distinct radial structure, sometimes is concentrically strati- 

 fied and contains numerous granules which are also to be found in the tri- 

 chogenic cells. This is evidently a fluid, which has either passed through the 

 hypodermis and is a derivate from the fat-body or it is a secretion produced 

 by the hypodermis and is coagulated by the method of fixation. . . . 



The above stated facts concerning the relation of the fat-body to the 

 hypodermis and the cuticle differ in some essential respects from what Was- 

 mann has found in the termitophilous physogastrous insects studied by him. 

 In Spirachtha, Termitoxenia, the larvae of Orthogonius and Glyptns, in Xcno- 

 ^aster and other Aleocharini the hypertrophied fat-body is always surrounded 

 by large tracts of blood-tissue, consequently the exudation is derived di- 

 rectly from the blood-tissue and only indirectly from the fat-body. The 

 exudation is no fluid but evaporates through the membranous cuticle, which 

 has no pores. 



To support the theory of the exudation being only an attractive odor and 

 not offering the termites any source of subsistence Wasmann points out the 

 fact that the symphili as a rule only occur in small numbers in the nests. 



These statements, however true they may be with regard to the above 

 mentioned genera, do not apply at all to Tcrmitoiiiimns. In this genus on the 



