118 SPOLIA ZBYLANICA. 



The hosts are species of the great black wood-boring bees, very 

 common in Ceylon, of the family Xylocopidae belonging to the 

 genus CojJtorthosoma* This genns is characterized principally 

 by the structure of the basal segment of the abdomen, which fits 

 against the hinder wall of the thorax. This segment is attached 

 to the thorax by a somewhat narrow pedicle below ; the rest of 

 the front wall of the segment presents a sharply truncate free 

 border and a concave anterior surface. When the border of the 

 basal abdominal segment is closely applied to the thorax a closed 

 chamber is produced owing to the aforesaid concavity of its front 

 wall. "If," says Mr. Perkins,t "the basal concavity of the first 

 abdominal segment be examined in the female bee, a distinct 

 orifice will be found in the middle, generally small and overhung 

 with hairs, but in some species large and quite exposed." 



This orifice leads into a wide chamber which projects back- 

 wards, filling a large part of the interior of the segment.:}: 



The chamber is inhabited by species of mites (Acaridae), two 

 of which have been named Greenia perkinsi and Greenia alfkeni 

 by Dr. A. C. Oudemans. Sometimes the acarids are so numerous 

 as to fill the chamber, and occasionally they may be noticed 

 projecting through the orifice. Perkins found the chamber in the 

 females only of seven species of CoptortJwsoma, namely, G. latipes, 

 tenuiscapa, cestuans, verticalis, cmrulca, caffra, and trepida. The 

 last two species are from South Africa, the others from the Indo- 

 Malay region. 



The fact that the chamber is only found in the female bees is 

 interesting, because " the male bees are short-lived and vagrant, 

 rarely returning to the nest for more than a few days " [Perkins], 

 so that it is an advantage to the parasites to confine themselves to 

 the more stable females. Mr. Perkins, however, found that " not 

 every species of Koptorthosoma possesses the chamber, for Dr. 

 Willey has brought home from New Britain females of a species, 

 very closely allied to K. cvstuans, which show no more trace of it 

 than do the males of those species above mentioned." 



Also no species of the genus Xylocopa in its restricted sense 

 were found to be provided with an acarid chamber in the 

 female. 



* Sometimes written '■• Koptorthoaoma." 



t R. C. L. Perkins. On a special acarid chamber formed within the basal 

 abdominal segment of bees of the genus Koptorthosoma (Xylocopinaj). Ent. 

 Monthly Mag. (second series), vol. X., February, 1899, pp. 37-39. 



X A drawing of the chamber showing the position which it occupies in fhe 

 body of the bee is reproduced in a paper entitled " On some Parasites of Xylocopa 

 tenuiscapa, Westw.," by E. E. Green, in Ent. Monthly Mag. (second series), vol. 

 Xlil., October, 1902, pp. 232, 233. . . 



