EDITORIAL 51 



of the cocoon, where they are left by the larva, arranged 

 roughly in the form of a transverse belt just beyond the 

 middle. The spicules are picked up by the anal tuft opening 

 and closing, the abdomen of the moth being at the same 

 time contorted so that the tuft moves round and round the 

 cocoon. The eggs of this species are, as is well known, 

 eventually covered by the detached anal tuft of hair for 

 protective purposes, and the collection of the spicules for 

 the purpose of increasing the protective qualities of this 

 tuft is one of the most remarkable instincts that have been 

 recently discovered in the great class of insects. 



A paper of a very different character, but one of 

 importance to the systematic worker, is that appearing in 

 the same journal, by the Rev. F. D. Morice, on the specific 

 differences in the saws of Female Dolerids, 1 a group of 

 Sawflies in which the specific differences are admittedly 

 difficult of comprehension. By the help of the beautiful 

 photographic plates which illustrate this paper, and in which 

 the saws of all the European species are represented, students 

 of our British Hymenoptera will have their labours in 

 identification materially lessened, especially when the 

 accompanying text is studied at the same time. 



Some few years ago Mosquitoes seemed to be the 

 favourite subjects for study among economic entomologists, 

 and naturally so, owing to their connection with malaria, 

 but now-a-days the Common House-fly appears to have 

 become the popular insect. Two contributions to the 

 bionomics of this abundant Dipteron fall to be noticed this 

 month. The first of these is a paper by Dr Edward Hindle, 

 entitled "The Flight of the House-Fly," 2 in which the 

 results of experiments with over 25,000 specimens are 

 recorded. The flies were first caught and fed for twenty- 

 four hours to ensure the full development of their skeleton 

 and consequent powers of flight. They were then counted, 



1 Trans. En/. Soc, 1913, part 3, pp. 428-435, plates xxiii.-xxv. 



2 Proc. Cambridge Philosophical Society, vol. xvii., part 4, pp. 310- 

 313 (30th January 1914.) 



