ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 217 



what Keilin and Picado have described in Diachasma. It has loco- 

 motor appendages, primordia of the adult's internal organs, well-formed 

 empty tracheae without open stigmata. It moults and passes into a 

 second transition-phase. The third phase is helminthoid. The parasites 

 hibernate as larvge, and become winged insects after a short nymphal 

 period. 



Studies in Dyticidae.* — F. Brocher continues his interesting studies 

 on Dyticus niarginalis and D. punctulatiis, describing two pulsating 

 aspiratory organs (scutellar and metatergal) which seem to facilitate the 

 circulation of the blood in the wings and in the elytra. The dimensions 

 are about 1 mm. by 2 mm., large in comparison with various pulsating 

 organs which have been observed in other insects. In another paper t 

 the author discusses the process of respiration in detail. He calls 

 attention to the periods of somnolence, lasting ten to fifteen minutes 

 or more, during which there are no respiratory movements. When 

 Hydrophilus breathes at the surface it uses the pro-mesothoracic stigmata, 

 and shows rapid respiratory movements of the body, about twenty in 

 a minute. When Dyticus breathes at the surface it inspires by the 

 abdominal stigmata, and shows usually one inspiration. If it is in 

 critical need of air, it sometimes shows four or five rather weak inspira- 

 tions in a minute. Thus there is considerable diversity in the modes of 

 respiration. 



Abnormal Limb in Beetle. | — T. A. Chapman describes an unusual 

 abnormality in a beetle from the Bristol Museum, labelled Odontopus 

 cupreus(?), Portuguese East Africa. The third tarsal joint leads on to 

 the rest of the limb as usual, but gives off also an additional part with 

 two joints. These additional joints arise dorsally, and perhaps a medio- 

 dorsal portion of a normal tarsus has been reduplicated to form them. 



Salivary Glands of Male Panorpa.§ — L. Mercier calls attention to 

 the large development of the salivary glands in the males. In a young 

 imago, four or five days after emergence, they may be 2-3 mm. long ; 

 in one of eight days they may be 12-15 mm. This does not seem to be 

 connected with nutrition, for the young and the larvse feed just as the 

 adults do, and the two sexes are alike in their nutritive relations. 

 Observation of the pairing discloses a remarkable fact. The male emits 

 on the ground a drop of salivary secretion about the size of a pin's 

 head. This coagulates and looks like a pearl. The male removes 

 himself a little way. The female attacks the pearl with her rostrum 

 and envelops it with a brownish fluid from her crop. She remains 

 immobile, working at the hard drop, which she reduces to an irregular 

 magma. Meanwhile the male pairs with her. A second drop is often 

 used, perhaps after an interval of twenty minutes. The pairing process 

 lasts for about an hour ; so if the female rejects or finishes with the 



* Arch. Zool. Exp^r., Iv. (1916) pp. 347-73 (11 figs.). 



t Arch. Zool. Exper., Ivi. (1916) pp. 1-24 (6 figs.). 



X Trans. Entomol. Soc. London, 1916, pp. liv-lv (1 fig.). 



§ Arch. Zool. Exp6r., Iv. (1915) Notes et Revue, No. 1, pp. 1-5 (1 fig.). 



April 18th, 1917 q 



