1881.] 



MICKOSCOPICAL JOURNAL. 



167 



a mucor ; no mycelium could be seen. 

 On placing some of the material 

 under the microscope with a 2-inch 

 objective, the globular bodies were 

 seen to be filled with spores, and 

 closely resembled the spore-capsules 

 of mucor, save in being larger and 

 lighter colored, but still no mycelium 

 was seen on the surface of the oat- 

 hulls, fragments of stems, etc., to 

 which the globular bodies adhered. 

 But on picking off, with a mounted 

 bristle,some of the globes and examin- 

 ing them separately on a slide, they 

 were found to have legs, and to be, in 

 fact, minute, hexapod acari (?), dead, 

 and distended by the spores of some 

 (Sphaeriaceous ?) fungus which had 

 completely replaced the natural con- 

 tents of the body. With much diffi- 

 culty a view of the insect in situ was 

 obtained, which showed it to be in a 

 stiff, straddling and apparently un- 

 natural position, nearly head down- 

 ward, so that the head and legs were 

 concealed from view by the swollen 

 body above. On crushing the de- 

 tached specimens in water, the con- 

 tents of the body seemed to be 

 matted together, but many free spores 

 floated out, and were found to be 

 globular and hyaline and of an aver- 

 age diameter of o.ooi of an inch. 



This would seem to be a different 

 fungus from the Sporendonema musci, 

 which destroys the house-fly and 

 other insects ; but as all the speci- 

 mens not immediately examined were 

 soon afterwards accidently destroyed, 

 this cannot positively be determined 

 until others are found. Many insects 

 are known to be attacked by various 

 species of fungi, and beetles, flies, 

 moths, locusts and larvae of various 

 kinds have been recorded as the vic- 

 tims ; but I have never seen any in- 

 stance recorded of any insect smaller 

 than the mosquito being thus affected, 

 and to find these minute acari thus 

 destroyed by such a vegetable para- 

 site is, to me at least, a new revelation. 



That these acari were killed by the 

 fungus, and not merely infested by it 

 after death from other causes, would 



seem to be an unavoidable conclu- 

 sion, from the fact that the insects 

 were found in their natural and 

 chosen abode, and under circum- 

 stances ordinarily favorable instead of 

 adverse to their well-being, and also 

 from the number so infested, their 

 peculiar, unnatural position, so close- 

 ly resembling that of the house-fly 

 when thus infested, the absence of 

 any apparent trace of the fungus out- 

 side the bodies, or on the material in- 

 habited by the acari, and from the 

 analogy of other similar cases of fun- 

 goid infection of insects. 



The number of the insects seen on 

 the spot on which the piece of board 

 had lain was thousands at the least ; 

 doubtless they were but a small part 

 of the whole number in the manure 

 pile, as considerable rubbish was 

 scattered upon it under which they 

 might have hidden 



How the insects became infested 

 with the fungus is an interesting 

 problem. In the case of larger insects 

 the natural openings of the body are 

 large enough to allow of the entrance 

 of mycelial threads or the passage of 

 spores, but in this case the spores 

 are much larger than any of the 

 openings of the body, and the 

 only trace seen of any threads of my- 

 celium or of any fungoid structures, 

 besides the spores themselves, were 

 a few excessively minute, glassy, aci- 

 cular fragments on which the spores 

 might have been borne. 



Terrestrial Diatoms. 



[An article by Mr. Julien Deby, 

 Vice-President of the-Belgian Micro- 

 scopical Society, printed in the Bul- 

 letin of that Society, in 1879, has just 

 been recalled to our mind by a re- 

 print in pamphlet form, and as the 

 subject is quite interesting we have 

 prepared the following condensed 

 translation of his article. — Ed.] 



In the month of May, 1848, Ehren- 

 berg presented to the Berlin Acade- 

 my of Sciences a note on the micro- 

 scopic tree-fauna of Venezuela. The 



