150 SUMMARY OF CURRENT RESEARCHES RELATING TO 



male beetles, yet all the variations can be grouped around two main 

 types. It does not appear that the variations can be utilised in classifi- 

 cation, for there are marked differences among the members of a single 

 family. In the first type, represented in the Carabidse, the Cicindelidae, 

 the Dytiscidae, &c, the testes are simple and tubular. In this case 

 the spermatozoa are chiefly formed in the proximal end of the tubes, 

 and these proximal ends are wound into a ball. The distal ends of the 

 two tubes are dilated and form seminal vesicles, which join the simple 

 tubular accessory glands at a point more or less remote from the ejacu- 

 latory duct. In the second type the testes are compound, and two sub- 

 groups are formed according as they are (A) arranged in fasciculi, or 

 (B) in grape-like masses. (A) This type is represented in Aphodiinre, 

 Chrysomelidae, Curculionidae, &c. ; in it the testes form two clusters of 

 ampullae, each ampulla having a short efferent canaliculus. The canali- 

 culi of each side open into the vas deferens of that side, and this is 

 dilated during part of its course to form the seminal vesicle. The 

 accessory glands meet the vasa deferentia at the top of the ejaculatory 

 duct, and the latter bears a vesicle at some part of its course. In the 

 sub-group (B), represented in Tenebriouidae, Silphidae, Elateridae, &c, 

 the ampullae of the testis at either side are placed in series along a 

 median tube which is continuous with the vas deferens. A seminal 

 vesicle is present, as in the other cases, but the accessory glands are 

 numerous, and varied in shape. As to histology, the author finds that 

 the chitinous intima is not a product of cellular secretion, but is due 

 to an actual differentiation of the cytoplasm of the underlying cells. 



Stridulating Organs in Beetles.* — C. J. Gahan comments upon 

 Schrodte's discovery of well-developed stridulating organs in the larvae 

 of several genera of beetles, and on the fact that the structures are 

 generally alike in both sexes of adults, though with some notable excep- 

 tions. He describes the stridulating organs on the head, on the pro- 

 thorax and front legs, on the mesothorax and middle legs, and on the 

 hind legs, elytra, and abdomen. 



Stridulating Organ of Rhynchota f — A. Handlirsch describes the 

 thoracic stridulating apparatus found equally on both sexes of all true 

 Beduviidae and Bhymatidae, but absent in Hemiocephalidae and Nabidae. 

 Another kind of apparatus — on the ventral surface of the abdomen — 

 occurs in Tetyrariae, and is described in detail. In a third group, that 

 of the Corisida?, a third kind of organ is found. 



Prothoracic Stigmata in Diptera.} — Dr. J. C. H. de Meijere has 

 collected the pupae of a number of Diptera, for the purpose of investi- 

 gating the peculiar breathing organs which are often present, and have 

 been described as homologues of wings. He publishes a brief preliminary 

 note in regard to his results. He finds that these peculiar breathing 

 organs have essentially the same structure as the abdominal stigmata of 

 the pupae, and can therefore not be homologised with wings. Further, 

 he finds that the anterior stigma of the imago is to be regarded as pro- 

 thoracic in position, and as originating from that of the larva. 



* Trans. Entom. Soc. London, 1900, pp. 433-52 (1 pi.). 



t Ann. HofmiiBi-um Wien, xv. (1900) pp. 127-41 (1 pi., 15 figs.). See Verb. 

 Zool.-bot. Ges. Wien, 1. (1900) pp. 520-2. 

 X Zool. Anzeig., xxiii. (1900) pp. 676-8. 



