400 SUMMARY OF CUERENT RESEARCHES RELATING TO 



In bees there is the same general structure, but the number of cell- 

 elements composing the organ is much larger. The organs seem to be 

 homologous throughout the Hymenoptera. But it is doubtful whether 

 those in Orthoptera are homologous with those in Hymenoptera. The 

 .organ begins to appear very early, in the eighth day after oviposition, 

 and is probably of very ancient origin. Schon inclines to regard the 

 chordotonal organ as adapted to the perception of sound-waves. 



Gynandromorphous Bee.* — Franz Maidl describes an interesting 

 case of lateral gynandromorphism in a carpenter bee, Xylocopa micans. 

 The head is male on the right, female on the left. But in the thorax, 

 limbs, wings, and abdomen the female characters are on the right and 

 the male on the left. The author discusses lateral, transverse, frontal, 

 and mixed gynandromorphism. 



Structure of Halteres.f — Hugo Pflugstaedt has studied the minute 

 structure of the halteres or " poisers " in Sarcophaga carnaria, CalUphora 

 erythrocephala, Si/rphus balteahis, and Eristcdis tenax. These remark- 

 able organs are full of sensory structures, which fall into three groups. 

 1. There are sensory papillae, ending in peculiar cuticular prominences, 

 and occurring in two forms, " basal " and "scapal." 2. There are 

 sensory sette on the heads of the halteres and visible externally. 3. There 

 are two chordotonal organs, a large one and a small one. In some way 

 which cannot be defined at present, the halteres are necessary for normal 

 flight. 



Chordotonal Organs at Root of Wings in Lepidoptera.|— R. Vogel 

 gives an account of the minute structure of these puzzling organs. 

 Some Satyridae show a well-differentiated tympanal area and large tra- 

 cheal vesicles, and the author adheres to the view that in such cases the 

 chordotonal organs have to do with the perception of sound. 



Development of Gonads in Caterpillars.§ — Karl Zick has studied 

 this, especially in Pieris brasskse, Vanessa io, and V. pioJychloros. The 

 larvifi are sexually differentiated when they leave the egg, and the males 

 can be distinguished from the females. The history of the testis is 

 followed in detail, and the author deals with the develonment of the 

 outer unpigmented envelope and the inner intensely pigmented reserve- 

 storing layer. There are special transport cells which connect this nu- 

 tritive inner layer with the testis. The apical cell has also a nutritive 

 function, but an important regulatory one as well. There is no strict 

 continuity between testicular envelope and efferent duct. 



Repugnatory Glands of Dytiscus.|| — Hans Blunck has studied the 

 glands in the thorax of Dytiscus from which a milky secretion flows out 

 when the insect is agitated. The fluid appears at the border Ijetween 

 prothorax and neck. There is a glandular complex embedded in the 

 fatty body and provided with a collecting bladder. Tlie gland -cells 



•■■= Verb. Zool. Bot. Ges. Wieu, Ixii. (1912) pp. 19-26 (5 figs.). 



t Zeitschr. wiss Zool., c. (1912) pp. 1-59 (4 pis. and 5 figs.). 



t Zeitschr. wiss. Zool., c. (1912) pp. 210-44 (2 pis. and 8 figs.). 



§ Zeitschr. wiss. Zool., xcviii. (1911) pp. 430-77 (2 pis. and 24 figs.). 



11 Zeitschr. wiss. Zool., c. (1912) pp. 493-508 (9 figs.). 



