356 EENEST WARREN. 



tendency for a veduction in the size of the head ; this is seen 

 both in the physogastric and defensive types. 



In Paracoi'otoca the head is held downwai'ds at an angle 

 ■of about 70°-80° to the horizontal. This feature is less marked 

 in Termitomimus and it is not characteristic of Aleochai'ine 

 Staphylinids. 



We now see that Paracorotoca exhibits some marked 

 modifications, most of which are shared by other phj^sogastric 

 Staphylinids from Africa, Malay region and South America. 

 These common characteristics do not indicate close genetic 

 affinity, but they are striking examples of the parallelism 

 of structure associated with a similar environment. For 

 example, although Paracorotoca in general appearance is 

 extraordinarily like Corotocafrom South America, yet there 

 are important differences, and in the characters which are 

 commonly used by sj^stematists it appears to be nearer phylo- 

 genetically to Termit optochus from the Malay region 

 than to any other described forms, although in general 

 aspect these two beetles are not markedly similar. It is 

 interesting to note that the closer genetic affinity corresponds 

 to a closer geographical connection between the two species. 



EXPLANATION OF PLATES XVI— XXI, 



Illustrating Dr. E. Warren's paper, " Observations on the 

 Comparative Anatomy of the Termitophilous Aleocharine 

 Paracorotoca akermani [Warren)." 



Explanatory References. 



a. Aorta, a.e.o. Anal eversible organ, a.g. Accessory gland, a. I. 

 Antennary lobe. a. m. Articiilating membrane, a. n. Antenuary nerve. 

 a. p. Antennary pit. ah. Abdominal nerve mass, ah.ij.m. Abdominal 

 ganglionic mass. ah. r. Abdominal ridge, ab. s. Abdominal swelling. 

 ab. sw. Abdominal swelling, al. Ala. ao. Aorta. 



h. Bridge of pi'ocerebral lobes, b.p. Basal piece, hl.t. Blood tissue. 



c. Cornea, c. c. Procerebral commissiire. c. cJ. Cone-cells, c. 1. 

 Corpus luteum. c. p. s. Reticular cuticle of prothoracic swelling, ca. 



