86 



It appears probable that the relapse in man and animals may be 

 dne to the development of fresh crops of spirochaetes from granules 

 formed by the organism that caused the first attack [c/. R.A.E., 

 B, vi, 138]. 



Observations upon other pathogenic spirochaetes make it probable 

 that a similar cycle of development is common to them all. 



MacArthur (W. p.). An Abnormal Development oJ Callip/wni 

 crythrocephala.—Jl. R.A.M.C.. London, xxxvi, no. 3, INlarch 

 1921, pp. 232-233. 



Of several thousand examples of Calliphora erythrocephala that were 

 bred for experimental purposes, six were observed to develop in a 

 peculiar manner, the normal position within the puparium being 

 reversed, and the head of the imago directed towards the posterior 

 spiracles. The pupal case ruptured at the usual site, but none of the 

 insects managed to free themselves. In 500 pupae subsequently 

 dissected, one insect was found lying reversed in this manner. 



Newstead has described a similar occurrence in the case of Aiich- 

 meromvia luteola, but this phenomenon does not appear to have been 

 recorded for any other species of Muscids. Experiments are being 

 carried out with the object of ascertaining the cause of this remarkable 

 development. 



Pierce (W. D.). Lectures in Applied Entomology : Vol. 1. The 

 General Subject of Applied Economic 'Exiiomology.— Denver, 



Colorado, The Mineral Metal and By-Products Company, 1920-21, 

 220 pp. multigraph. 



This is the first volume of a course of lectures on Applied Entomology. 

 The course is not designed to deal with injurious and beneficial insects 

 in the manner of an ordinary text book, but rather with methods 

 and principles. The average entomologist has, owing to the vastness 

 of the science, been forced to specialise on only a limited part of 

 economic entomology, and so requires a concise summary of the field 

 before him in order that he may render the best service. 



The first volume of the course comprises ten lectures on general 

 aspects of the subject, including one on the entomologist in relation 

 to sanitation. 



Hearle (E.). The Larva and Breeding-place of Acdes aldrichi, Dyar 

 and Knab. (Culicidae, Diptera). — Canad. Ent., London, Out., 

 liii, no. 2, February 1921, p. 48. 

 Aedes aldrichi breeds in wooded river bottoms in the Lower Eraser 

 Valley in British Columbia. During flood time these areas are con- 

 verted into temporarv swamps. .4. aldrichi is the chief species found, 

 but .4. vexaiis and .1. cinerciis also occur. 



Gill (C. A.). The Influence of Humidity on the Life-history of 

 Mosquitoes and on their Power to transmit Infection. — Trans. 

 K. Soc. Trop. Med. (F- Hvg., London, xiv, no. 5, 21st January 

 1921, pp. 77-83. 



The experiments here described were carried out in India with 

 Culex faiigans and bird malaria (Proteosoma grassii). They indicated 

 that a" mean relative humidity of not less than 48 per cent, (at a tem- 

 perature of 27X, [80-6°F.]) is essential to the existence of C". faligans 



