420 SUMMARY OF QUERENT RESEARCHES RELATING TO 



observations of many naturalists brought together in this useful form. 

 The predaceous orders dealt with in the present section are Diptera, 

 Neuroptera, Hemiptera, Orthoptera, and Coleoptera. Certain general 

 conclusions of interest are suggested by a study of the lists, and these 

 are discussed by the author. The Hymenoptera, Diptera, Coleoptera, 

 and Lepidoptera, placed in the order of importance, account for nine- 

 tenths of the recorded prey of the Asilidte. Other orders are of small 

 importance, but it is a striking fact that Acridiid^ (Grasshoppers) are 

 the only recorded prey among the Orthoptera, and Cicadidte (with the 

 exception of a single Cercopid) among the Rhynchota Homoptera. 

 Amongst the prey of the Asilid^e there is a great predominance of 

 Hymenoptera, including stinging members of the order ; of Coleoptera 

 half the families contributing victims are looked upon as specially 

 protected. These are but a few of the many interesting facts revealed 

 by a study of the 362 separate observations tabulated in this memoir. 



Mid-gut Glands of Beetles.* — Jan Hirschler has studied in 

 embryos of Donacia the origin of tlie sub-a3sophageal organ. He finds 

 that it has an endodermic origin, and that it is a true liver-like mid-gut 

 gland of paired origin comparable to the liver of Crustaceans, and 

 perhaps to be interpreted as a vestige which attained greater develop- 

 ment in more primitive air-breathing Arthropods. 



Development of Mid-gut in Trichoptera.f — E. Russ gives some 

 notes on the post -embryonic development of the mid-gut in AnahoUa 

 Imvis Zett. There are cell-nests upon the basal membrane which 

 proliferate and spread out into an epithelium. This raises the larval 

 epithelium which, getting detached, passes into the cavity of the gut 

 and forms what is known as the larval yellow body. The secretion of 

 the new epithelium hastens the solution of the larval yellow body, so 

 that at the end of the larval rest-period there remain no traces of it in 

 the mid -gut. The yellow body of the pupa, which differs in origin and 

 structure from that of the larva, is also described. 



Anopheles Larvae in Flax Pits.| — A. Bongiovanni finds that a 

 toxin capable of killing larva of AnopheJes is developed in flax-steeping 

 pits in Italy if there is a rapid rise of the temperature to 30°-:i2° C. The 

 significance of this as a means of checking the distribution of malaria is 

 indicated. 



Bionomics of Culicid8e.§— B. Galli-Yalerio and J. Rochaz de Jongh 

 have investigated a num])er of points in the natural history of Culicid 

 genera. With regard to the early spring mosquitos, they find that these 

 arise not from the early laying of eggs by females which survive the 

 winter, but from larvas and eggs which have lasted throughout the 

 winter. They find that Lemiia falustrk may play an important part in 

 hindering the development of Anopheles, while, on the other hand. 

 Nasturtium officinale and Ranunculus aquaticus favour the deposition of 

 eggs. Wind is not regarded as of much significance in the distribution 



* Zool. Anzeig., xxvi. (1907) pp. 766-70 (4 figs.). 

 t Tom. cit., pp. 708-10. 



X Centralbl. Bakt. Parasitenk., xlii. (1906) pp. 702-5. 

 § Tom. cit., pp. 468-77. 



