I02 PRESIDENTIAL ADDRESS SECTION D. 



ing fluids. In these two beetles salivary glands of the usual 

 type could not be traced, and consequently there can be little 

 or no reciprocity in the matter of saliva feeding. 



We now see that the physogastric condition of termitophiles 

 arises in a number of ways, and the causes which produce it 

 are accordingly diverse and complicated. 



3. The Physogastric Staphylinids of Different Zoological 

 Regions. — In three termite regions, which have been especially 

 studied, namely, South America. Indo-Malay Region, and Africa, 

 we find a very interesting parallalism in the development of this 

 peculiar physogastric condition among the Staphylinid termito- 

 philes (Plate 10). 



In the Indo-Malay Region, starting from a comparatively 

 unmodified beetle, such as a species of Mynnedonia (A), we 

 pass by a series of species to a maximum type, Tcrmitoptochus 

 (F), recentlv described by Silvestri. The upturning and for- 

 ward extension of the abdomen increase as the physogastrism 

 becomes greater. In the Ethiopian region there are two types : 

 (i) Where the inflated abdomen is not upturned, and (2) where 

 the upturning does occur ; the maximum stages being respectively 

 Termitobia (H) and Tcrmitomimus (L). In South America we 

 also have the same two types reaching extremes in Timeparthemus 

 (M) and Spirachtha, (Q) respectively. Two roughly parallel 

 stages in the three regions are represented by Termitotima and 

 Termitoptochus in the Indo-Malay Region. Para'coro'toca and 

 Terniitomimns in Africa, and Corofoca and Spirachtha in South 

 America. 



As we pass down to the extreme types of physogastrism 

 there may be noticed a gradual reduction in the labium ; the 

 paraglossa and lingua become greatly reduced or lost, and the 

 labial palps shorten excessively and lose most of the joints. 

 This modification of the labium accompanying physogastrism is 

 regarded by Wasmann as being due to the loss of function re- 

 sulting from the termitophile being fed by the termites. It 

 must be remembered, however, that the great development of 

 the mandibles unmistakably points to a partial continuance of a 

 carnivorous habit. 



4. The Dispersal of Termitophiles. — The method of the 

 dispersal of the species in certain termitophiles is exceedingly 

 obscure. This is more especially the case when the termito- 

 phile is highly specialized and passes all stages of its life within 

 the termite nest. The imagos of the moth and dipterous termito- 

 philous larvse mentioned above are doubtless free-living, and 

 eggs could be laid at the entrance to the nest; but in the case 

 of viviparous, physogastric staphylinids and the physogastric 

 dipterous Tcnnitoxciiia. which cannot withstand desiccation, or 

 live for any length of time outside the nest,, the means for dis- 

 persal are not clear. In Natal, the imago of Paracorotoca is 

 exceedingly scarce, and there may be only a single specimen in a 



