ENTOMOLOGY 563 



G. H. D. Carpenter [Trans. Ent. Soc, 1921, 1-105) records 

 a number of experiments on the relative edibility of insects, 

 using a single monkey {Cercopithecus) as the judge of the 

 question. As the result of nearly 1,000 experiments, the 

 behaviour of this monkey has led the author to the conclusion 

 that conspicuous insects are definitely distasteful, and make 

 the most of their conspicuousness to advertise the fact. Highly 

 edible species endeavour to elude their enemies by concealment. 

 Edibility and distastefulness, it is pointed out, are not absolute 

 but relative qualities, and a hungry monkey will eat an insect 

 which he would pass over when not very hungry. G. C. 

 Crampton has published a further series of papers on general 

 insect morphology. In Journ. New York Ent. Soc. (29, 63-100) 

 he discusses the phylogenetic origin of the mandibles of Arth- 

 ropods, and points out, as others have done before him, how 

 close a similarity is exhibited in the mandibles of the Machilidae 

 with those of certain of the higher Crustacea. In a larger 

 contribution {Ann. Ent. Soc. Am., 14, 65-103) he enters into 

 a detailed morphological discussion of the head-sclerites and 

 mouth-parts of various orders of insects. It is too elaborate 

 for a brief abstract in these pages, but is a paper which concerns 

 all morphologists. Reference has already been made in my 

 previous article on " Recent Advances " to this author's pre- 

 liminary announcement of his rejection of the view that the 

 maxillulse of insects are a true pair of head appendages. In 

 Psyche, 28, 84-92, he has stated his views in greater detail 

 and concludes that the work of Folsom is not to be relied upon, 

 mainly, it appears, for the reason that it is not in accordance 

 with the findings of another observer — Philiptschenko, who 

 was unable to find appendicular rudiments of maxillulae in the 

 embryos of an allied insect. As the matter stands at present, 

 it is scarcely possible to say whether it is Folsom or Philip- 

 tschenko that has committed an error of observation. It must 

 also be pointed out that, in certain of the Thysanura, each 

 maxillula exhibits an apparent differentiation into galea, lacinia, 

 and palpus. This differentiation is not regarded by Crampton 

 as a real one ; nevertheless, he does not completely succeed in 

 explaining it away. H. Onslow {Phil. Trans., 211, 1-74) has a 

 valuable contribution on the causes of the irridescent colours 

 in various insects and on a periodic structure in the scales. 

 Irridescence is found to depend very largely upon interference 

 and not upon diffraction. In the case of Lepidoptera, the 

 interference theory is greatly strengthened by the discovery of 

 a regular periodic structure, of the correct magnitude, in certain 

 irridescent scales. The elytra of nearly all scaleless irridescent 

 Coleoptera form a group whose colour appears to be due to 

 selective metallic reflection. 



