428 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Locke and Ptychoparia striata Emmr. The ventral integument is a 

 thin uncalcified membrane, which may be divided into pleurosternites 

 and mesosternites, corresponding to the mesotergites and pleurotergites 

 of the dorsal test, and like them connected segnientally by an inter- 

 articular membrane. The mesosternites are usually marked by five 

 longitudinal ridges, or buttresses, representing thickenings of the mem- 

 brane, which may be homologised with apodemal structures in (other) 

 crustaceans, and not with the appendicular system. These buttresses, 

 or apodemes, include a single median one for each mesosternite, with 

 two others on each side extending forward and obliquely inward, and 

 enclosing subtriangular or rhombic spaces. The presence and disposi- 

 tion of these buttresses apparently afford information regarding the 

 ventral musculature of the Trilobites. A pair of flexors is indicated, 

 together with lateral strands attached to each mesosternite and extend- 

 ing forward and inward to their union with the main bundles within 

 the cavity of the next anterior somite. 



a. Insecta. 



Artificial Parthenogenesis of Silk-Moth Ova.* — A. Tichomirow 

 refers to his experiments in 1885 in which he showed that unfertilised 

 ova of the silk-moth (Bomhyx mori) dipped in dilute sulphuric acid 

 exhibited parthenogenetic development in response to the extraordinary 

 stimulus. He has since experimented with similar results with dilute 

 sulphuric and hydrochloric acid. His conviction is that the induced 

 development is very different from the normal. The embryos have 

 little vitality, the cells have exceedingly little coherence, the relations 

 of the germ-layers is abnormal, and so on. In short, the artificial 

 parthenogenetic development is a Kruppelentwicklung. 



Prothoracic Respiratory Apparatus in Dipterous Pupae.f — J- C. 

 H. do Meijere finds that, except in Chironomus, this apparatus is a 

 modification of the Tilpfelstigmen which are of wide occurrence in 

 simpler form in Dipterous larvae and on the abdomen of pupje. He 

 discusses the development and the possible homologies and the many 

 different forms. 



Some British Hemiptera4 — E. A. Butler writes a useful popular 

 paper on what he calls " stilt-walkers " — Metatropic rufescens from the 

 Enchanter's Nightshade, Metacanihus punctipes from the rest-harrow, 

 Neides tipularius, Ploiaria vagabunda, Hydrometra stagnarum, and 

 Banatra linearis. 



Index to North American Orthoptera.§ — S. H. Scudder has com- 

 pleted an index, which has been forty years in the making, of all known 

 definite references to the Orthoptera of North America and the West 

 Indies from the time of Linne to the close of the last century. The 

 list of literature cited is practically a complete bibliography of North 

 American Orthoptera. 



* Zool. Anzeig., xxv. (1902) pp. 3S6-91 (3 figs.). 



t Zool. Jahib., xv. (1902) pp. K23-92 (4 pis.). 



X Knowledge, xxv. (1902) pp. 97-100 (6 figs.). 



§ Occasional Papers Boston Soc. Nat. Hist., vi. (1901) vi. and 436 pp. 



