34-8 Massee: Mycological Research in the United States. 



exceptionally pachydermatous, are often regretted in after years. 

 Dr. Thaxter wisely avoided all such pitfalls, and, settling- down 

 as a specialist, has, after some years of study, produced one of 

 the most important, as also one of the most beautifully illustrated 

 of monographs ever written on a mycological subject. This 

 work, entitled ' Contributions towards a Monograph of the 

 Laboulbeniaceai,' forms Vol. XII., No. III., of the ' Memoirs 

 of the American Academy of Arts and Sciences,' 1896. 



The monograph deals with the morphology, life-history, and 

 systematic arrangement of a family of minute fungi, the majority 

 of which are external parasites on insects, species belonging to 

 the coleoptera, especially aquatic forms, being the most favoured 

 hosts, although members of other groups of insects are also 

 attacked, the common house-fly having furnished some very 

 interesting forms. One species occurs on the larva of a white 

 ant, and one on an Acarid. 



The vegetable nature of these minute organisms was first 

 recognised by Robin, a Frenchman, in a classical work entitled 

 ' Histoire Naturelle des Vegetaux Parasites,' but up to the 

 period of Thaxter's investigations only about half-a-dozen 

 species were known, and these were very imperfectly under- 

 stood, and their great importance, from a biological and 

 taxonomic standpoint, entirely unsuspected. 



The species are all minute, in fact coming under the category 

 of microscopic fungi, one millimetre in length being above the 

 average. The general appearance of these fungi on the host is 

 described as follows by Thaxter : — 'When examined in situ on 

 the host insect they appear in general like minute, usually dark- 

 coloured or yellowish bristles or bushy hairs, projecting from its 

 chitinous integument, either singly or in pairs, more commonly 

 scattered, but often densely crowded over certain areas, on which 

 the}- form a furry coating. 



Unlike other fungus parasites on insects, as the species of 

 Cordyceps , etc. , the species of Laboulbeniaceae do not appear to 

 prove injurious to the host, at all events not to the extent of 

 causing death, or even a serious epidemic. 



The forms presented by these minute fungi are very varied 

 and often very beautiful, but the chief interest in the group 

 centres on the sexual mode of reproduction, which in all 

 essential points corresponds with that of the 'Florideae or red 

 seaweeds. The female organ consists of a trichogyne or slender 

 projecting filament to which the passive or motionless antheridia 

 adhere, and thus effect fertilisation, and a carpogenic cell, the 



Naturalist. 



