CO SUMMARY OF CURRENT RESEARCHES RELATING TO 



Hymenoptera of West Indian Islands.* — W. A. Schulz describes 

 a number of Aculeate Hymenoptera from the "West Indies. About 1300 

 Hymenoptera are now known from the Antilles, and it seems probable 

 that this is only a small fraction of the existing species. The paper 

 gives a good example of the need of caution in making species ; Pepsis 

 rubra and P. stellata are the dimorphic sexes of P. rubra. 



Ergatogynic Ants.f — Margaret Holliday ' has made a thorough 

 examination of numerous species with a view of determining the relative 

 sexual conditions of the queens and workers. She finds that the ovaries 

 of ithe workers of most of the species investigated show a reduction 

 in the number of tubules, but they are not rudimentary. Morpho- 

 logically and histologically they are capable of producing and do 

 produce eggs. The presence of the receptaculum seminis is not peculiar 

 to the queen ant and cannot be used as a distinguishing feature. There 

 is no physiological reason why those workers possessing the receptaculum 

 should not have the power of performing the function of the sexual 

 female, and it is believed that they do so. The author does not think 

 that intermediate conditions of fertility are induced by direct changes in 

 social conditions, as has been held, but thinks a phylogenetic explanation 

 the better one. 



Males of Andrena.J — E. Frey. Gessner describes the males of 

 Andrena ccneiventris Mor., A. incisa Evers., A. parviceps Krchb., and A. 

 rogenhoferi, which were not known when Schmiedekneeht published his 

 monograph on the Bees of Europe. The author has found the males of 

 the four species noted, and Morawitz has also described the male of A. 

 incisa. 



Habits of the Drone-Fly.§ — W. H. Harris gives an account of the 

 emission of musical notes and of the hovering habit of Eristalis tenax. 

 He shows that the musical notes are not due to the rapid vibrations 

 of wings or poisers, nor to the rapid motion of the legs, but to the 

 expulsion of air from the trachea) through the spiracles. In each 

 spiracle there are two chitinous crescent-shaped rods joined together by 

 a ligament and thus forming a bow with elongated free arms. The 

 rods support very delicate and pliant membranes which are folded or 

 plicated in a very complicated manner. When the air is expelled and the 

 free edges of the plicated membranes are brought together by the 

 thoracic muscles the musical notes are produced. He finds that the 

 power of hovering is due to specialised or auxiliary organs. In Eristalis 

 tenax it is due to the four alulets and to a newly discovered organ which 

 he calls the " plume." These organs are attached near the bases of the 

 wings, and consist of a basal part of chitin and a membranous hollow 

 expansion with long hairs attached. 



Habits of Chironomus.|| — T. H. Taylor contributes some notes on 

 Chironomus sordidellus. He describes the way in which it converts its 



* SB. K. Akad. Wiss. Munchen (1903) Heft. iii. pp. 451-88 (7 figs.), 

 t Zool. Jahrb., xix. (1903) pp. 293-328 (16 figs.) 

 % MT. Schweiz. Entom. Ges. xi. (1903) pp. 40-5. 

 § Joum. Quekett Micr. Club, viii. (1903) pp. 513-20. 

 || Trans. Eut. Soc. Lond., 1903, part iv. pp. 521-3. 



